Practicus In The Studio: Studio Exposures.

            Correct exposure is one of the most important of the factors in making perfect photographs, yet the majority of portra approach it in the most casual manner, and apparently trust to a sort of sixth sense to tell them how long to keep the shutter open, or as one Mid to me, "It is like taking a dire into water; when I press the bulb, I do not know when I am coming to the surface.” With long practice it is possible to work successfully in this sab-conscious way, but most people will find it desirable to have some definite idea of the number of seconds necessary to give the exact quality of negative which is aimed at. I want you to take particular notice of those last words. There can be no fixed standard of exposure or density in portrait work, or we should all arrive at one monotonous style, without that touch of individualism which now distinguishes our best photographers from one another. Twenty or thirty years ago there was an established ideal of a clear, sparkling negative ranging from clear glass to opacity, and a high-class operator who did not conform to it had little chance of employment. Many negatives which would be appreciated to-day were then thrown aside as failures, because they were too soft or too hard to print in the limited range of media then available, but now we are more free to choose our methods, and can produce negatives to satisfy our own artistic instincts. Therefore it is necessary if we are to be consistently good in our work we must not trust to "flukes" for our successes, but to study the conditions under which our particular class of negatives can be obtained.
            On asking one of our best known outdoor photographers bow he secured such uniformly perfect negatives. I was told that they were obtained by "exposing to suit the developer.” This was in the pre-Watkins days, when no attempt had been made to systematize development and most people believed that the clever worker owed his success to modifying the developer according to the appearance of the imago, often beginning with plain pyro solution, and working up the negative by adding alkali and bromide drop by drop. This idea is now exploded, proving that my friend was a true prophet when he asserted that the prime factor in producing the negative was correct exposure Hurter and Driffield, to whom photographers owe so much, have taught us that the amount of silver affected by light when a plate is exposed is in definite proportion to the length of exposure given, bat this assumes that all the so affected is reduced by the developer, or, in other words, the plate is “developed right out," which is rarely the case in studio work, most portraitists finding that such a procedure produces too much contrast. This fact has been recognized by both plate and developer makers who prescribe different times of development for portrait, landscape and copy negative, the former always being much shorter than the latter two.
            To establish a correct method of exposure we must make a few experiments, working with a standard developer, and a fixed time of development, which may be obtained by the factorial system, the only variation being made in the exposure. It is convenient and economical, besides assuring uniformity of rapidity in the emulsion, to make several exposures on one plate, and this can easily be done in most studio cameras by fixing a small mask in the camera back and marking the slide so as to show when the plate is in position. The easiest size is to work three upon a half-plate, cutting a mask with opening two inches by four and fixing this in the existing carte or cabinet mask. If the slide has notches for single exposures, and also for repeating two C.D.V. on half-plate, the centre notch may be used, but new marks s little farther from the centre must be made for the two end exposures. For my own use I have made a repeating back which allows of four exposures, each three inches by two clear, from the rebate upon a half-plate, and this I find handy for many other purposes.
            The exposures, which must, of course, be upon the same subject, may be varied in any proportion which the operator desires. Usually double at each step will be found as good as any for portrait work, as our negative will then show us the effect of one, two, four, and eight seconds' exposure. The result will be rather surprising to those who try it for the first time; for, supposing that the one-second exposure gives a thin but printable negative, it will be found that the eight-seconds section, although thick and slow to print, will also yield a passable result. That, however, is not my point, which is that the operator should now select the exposure which gives him the quality of imam- he wants, or if none quite pleases him should give an exposure between the two which he judges to be nearest correct. So far so good. Now all depends upon correctly estimating the value of the light, and this can better be done with an exposure meter than by the exercise of personal judgment. If we use an ordinary Bee meter and note the time taken to match the tint at the. time of making our exposures we shall be able to establish a ratio between meter time and exposure for any light or lighting. For example, if we find that our selected exposure is four seconds, and that it took right minutes to get the tint, we haw the proportion of half a second for each meter minute. Naturally I do not propose that anyone should make meter tests while sitter waits, but an occasional test between whiles can easily be managed. The plate speed and lens aperture must be unchanged, or due allowance must be made, or this system will be worse than useless.
            It is often found that when strong effects of light and shade are being tried for that the negatives turn out hard and chalky and do not at all represent the model as seen by the artist. There are two causes of this, both closely connected, under-exposure and over-development, the latter being due to an attempted to force out shadow detail. Now, if development had been done by time without regard to the appearance of the image, we should have retained the detail in the high lights, but the shadow detail would still have been wanting. Longer exposure would remedy this without giving flatness, unless-unite an unreasonable time were given. This class of subject affords an excellent field for the progressive series of exposures already recommended; or if it be thought that the effect cannot be judged from so small s plate two full-sized exposures may be made, one receiving three times as long as the other, both being developed for the same time in the same dish.
            It is important when making experiments in exposure to keep not only to one make of plate, but to the same grade. Emulsions vary in character, and two grades which are, perhaps, marked 200 and 240 H and D, cannot be relied upon to give the same quality of image, even if the difference in speed be accurately allowed for; much more is this the case if two makes of plate he mixed up. For the same reason one developer should be adhered to, and for printing quality land adaptability to various subjects and lightings there is nothing to beat the old-established pyro-sods. Remember that a negative is only a means to an end, and that "pretty" negatives do not always give the best of prints. Although not strictly within my subject, I feed that at the present time of year it is not amiss to on that pyro is less affected in its action by variations of temperature than most other developing agents. I have only recently found the slow action of another developer mistaken for under exposure, with the result that the exposures were increased and flatness resulted.
            A point which mart not be missed is the effect of the distance between lens and sitter upon exposure. This is always allowed for in copying, but is often overlooked in portraiture. Most operators know that a large head requires more exposure than a full length, other things being equal, but perhaps could not toll you why. There are two reasons, one being the increase in the focal length of the lens a the sitter approaches the camera, and the other the flattening of the lighting by the greater amount of atmosphere which intervenes as the sitter is placed further from the camera. Let us consider the former case, assuming that a head measures 9 inches in height and we are making a 3 in. image of it: this adds one-third to the camera extension, supposing we are using an 18 in. lens working at F/6 for infinity; one-third added to the focal length gives us 24 ins - in other words, we are working at F/8, which requires practically double the exposure. When taking a full-length cabinet the reduction would be l/12th, which would only add an inch and a half to the original focal length, and this we could safely ignore so far as exposure is concerned. In the second case the increase in exposure is only apparent, not real. If there is a certain amount of fog over the shadows it covers the bare glass, but there is no more detail in the shadows than there would be if the atmosphere were perfectly clear. In London, where the atmosphere is as thick in winter as it is in most places, many photographers use a lens of shorter focal length than they would otherwise, in order to avoid this flattening.
            In conclusion, let me impress upon the notice that correct exposure is the key to satisfactory results. Leaving colour effects out of the question, any arrangement of light and shade can be correctly reproduced if the proper exposure be given. We can flatten the scale by over-exposure, we can sharpen it by under-exposure, so that if we hit the happy mean we shall get upon our negative what we saw when looking at the sitter. Surely such a consummation is worth taking pains to attain, instead of following the usual "hit or miss" way.

PRACTICUS.

A NEW YELLOW DYE AND LIGHT-FILTERS MADE FROM IT.

           In the early days of orthochromatic photography the dye generally used for the preparation of light filters was picric acid, this having the advantage of simplicity and cheapness and of great efficiency, picric acid absorbing the ultra-violet almost completely, and having a wry sharp cut in the spectrum. The disadvantage of picric acid, however, is that it is unstable to light, filters made with it soon turning brown. For this reason the early gelatine filters were made chiefly with tartrazine, which is very stable and gives permanent niters. Tartrazine, however, has the disadvantage that its absorption in the ultra-violet is unsatisfactory, and even moderately deep tertrazine filters transmit appreciable amounts of ultra-violet, this detracting very much from their efficiency. For this reason filter yellow, introduced by Hoechst in 1907, rapidly displaced tartrazine as the best dye for filter-making, and has held that position ever since.
           Filter yellow is extremely stable, absorbs the ultra-violet strongly with the exception of a transmission band at 300μμ, which, since it is absorbed by glass, is of little importance, and hat a satisfactorily sharp out for the preparation of orthochromatic filters. A disadvantage of filter yellow which has always been recognized, however, is the fact that its absorption curve was less sharp than that of picric acid, and for many purposes, especially the preparation of very light filters, a dye possessing the stability and ultra-violet absorption of filter K, but of greater sharpness of cut, would be desirable.
           When the need for light-filters of high efficiency for aerial photography arose the need for such a dye became pressing, and we undertook a search for such a material. After a great number of trials it was found that suitable absorption and stability were possessed by the phenyl-glucosazones.
           When certain sugars, such as glucose, are warmed with a solution of phenyl-hydrazine in dilute acetic acid, yellow precipitates are produced possessing definite crystalline structures, by which the sugars may be characterized. These yellow substances are known as osazones, those formed with phenyl-hydrazine being termed phonylosazones. On measurement of the absorption spectrum of glucose-phenylosazone it was found that the absorption curve was very sharp and extended far into the ultra-violet, and since the material is well known to be stable, it appeared that a dye prepared from it would possess the properties required for the preparation of light yellow filters.
           Glucose-phenylosazone is insoluble in water, so that to obtain a dye it is necessary to have a salt-forming group present in the molecule, and to produce a dye suitable for use with gelatine it was desirable that this group should be an acid one. To obtain such a derivative of glucose-phenylosazone which will form salts with metals it is merely necessary to substitute for phenyl-hydrazine a derivative containing an acid group and condense glucose with it in the same manner. Several such derivatives were tried, and the most satisfactory result was obtained with glucose-phenyl-osazone-para-carboxylic acid. This was prepared in the following way:-
           Para-nitrotoluene was oxidized to give para-nitrobenzoic acid. This was then reduced to para-aminobenzoic acid, which was diazotized, and gave para-hydrazino-benzoic acid or phenyl-hydrazrne-para-carboxylie acid. The glucosazone of this acid is a yellow crystalline compound insoluble in water and almost insoluble in alcohol. It forms a sodium salt which is extremely soluble in water, but which can be precipitated from concentrated solutions by the addition of alcohol, and this sodium salt of glucose-phenyl-osazone-para-carboxylic acid has been adopted by us for the preparation of light-filters under the name of "Eastman Yellow."



In Fig. 1 are shown the absorption spectra of tartrazine, filter yellow, and Eastman yellow, from which it will be seen that the Eastman yellow has a sharper cut than filter yellow, and almost as strong an absorption in the ultra-violet.
           Light-filters prepared from it retain these characteristics, and these light-filters have been prepared and specified under the names of EK 1 and EK 2 light-filters. A special filter for aerial photography has been adopted by the American forces under the name of Aero No. 1.



Fig. 2 shows the absorption curves of these light-filters.
           As regards stability, it was found on test that the new dye was not quite so stable to light as filter yellow, but was superior to all other yellow dyes tried, and its stability is amply sufficient for the preparation of light-filters, since it requires weeks of exposure to direct sunlight to produce a change even in the lighter-coloured filters.

C. E. K. MEES.
H. T. CLARKE.

DARK-SLIDES OUT OF REGISTER

DARK-SLIDES OUT OF REGISTER.

           In three out of four studios that I have visited in the course of the last year or so, I found the dark slides of the camera in general use out of register with the focusing screen. The present use of rapid plates enables the photographer to use diaphragms to an extent that disguises considerably the want of fine definition, resulting from the plate not being truly in focus. In the days of wet collodion, when, in order to secure a portrait free from the unsharpness, due to movement of the sitter, it was the custom to use the lens at full aperture or nearly so, photographers had to be, and were, careful to see that their dark-slides were truly in register with the focusing screen.
           Although the want of sharpness in the negative, due to the slides not being in true register is less conspicuous when using the smaller apertures to which the use of rapid plates has accustomed us, it is still very desirable that the coincidence of position of the plate and the focusing screen should be as complete as possible, if only for the power obtained to get properly exposed results with the shortest exposures, particularly in the case of portraits of children. A photographer, the proprietor of a high-class establishment, doing a large business, writes me that since the correction of his slides his operator generally takes portraits of children with the open lens with excellent results, and with fewer failures and continent economy of time and plates.
           The plan which I employ to ascertain the truth, or want of it, of the registry of the slides, is to take a strip of wood about 3/5 or ½ an inch in thickness, rather longer than the width of the slide, and to drive a screw through it. The strip is laid across the front of the frame of the focusing screen, and the screw advanced until the point just touches the screen itself. A plate is now put in the dark-slide, the back is buttoned down, and the shutter is drawn. The strip is then laid across the front of the slide, and if it is in true register, the screw point will just touch the plate. It is desirable to repeat this trial with the plate placed both vertically and horizontally, and with each carrier that may be in use with the slide. A waste negative ix better than a plain glass for the purpose, as a paint scratch on the will indicate very closely coincidence of the two surfaces.

           The reason for having the wood a little longer than the width of the slide is (as I have found in one or two cases) that the top or bottom or one of the sides may be higher or lower than the opposite and the extra length of the wood allows the screw to be tried on different paris of the plate. The (crew is inserted at the place where it will come over the middle of the screen when one of the ends of the wood is just at the outer edge of the frame. This arrangement allows full use to l made of the extra length of wood for the testing the truth of adjustment away from the centre of the screen. The extent of deviation from coincidence is ascertained by placing slips of card of different thicknesses between the point of the screw and the focusing screen, or the plate as the case may be, until piece is found of a thickness that just fills the space.
           If it is the focusing screen that is found to be nearer to the front than the plate, a cardboard matt is rut of the same size outside as the ground glass; about a quarter of an inch wide all round except at the corners, where it is rounded inside for strength. A photographer generally has a stock of old mounts of various thicknesses, but if there is not one of just the thickness required, one or more thicknesses of cartridge paper may be pasted on to a thinner card, and when dry used for the purpose. The card matt is dropped into the frame, and the glass replaced and the slip-beading pinned in gain.
           If it ia the plate that is too near the front, slips of card are glued on all round to the rabbet of the dark-slide. It may be that some of the carriers may require adjustment independent of what has been done to the dark-slides. In this case they may be trued by gluing slips of card along the edges or the front, or, if the error is in the other direction, by reducing the thickness of the wood in the same place.
Of course, a neater job may be made by sending the slide and frame of the focusing screen to a camera maker or to an intelligent cabinet maker, if (which is not often the case) the camera can be put out of use for the time, but the home cure method described has answered perfectly well.

W. E. DEBENHAM.

EX CATHEDRA: Ghost Images or Flare, Camera Copies and The Shop Window.

Ghost Images or Flare

It is a known fact that many of the finest pre-war anastigmats frequently give both ghost images and flare when dealing with subjects which throw a strong light into their glasses. The defect is much lees often met when single lenses or the single components of convertible auastigtmats or R.R. instruments are employed. "Ghost images" or "flare'' are regarded by many photographers as being the more likely with instruments having many glass-to-air surfaces, and as a matter of fact, though not as a general rule, the more of these surfaces there are in the instrument the more likely is the defect to be in evidence in certain classes of work. It is not realized as well as it might lie by those who possess anastigmats which exhibit flare or ghost images that much may be done to assist in eliminating these if the instrument is provided with a sufficiently deep hood. We have in our own possession an anastigmat with no less than ten glass-to-air surfaces, and invariably when this lens is used against the light or under like conditions the defects are sure to manifest themselves, yet when the front glass is shaded with a deep and efficient hood we have never had the least reason for complaint. The rarity of ghost images or flare when R.R. or single lenses are used may be traced in part to the fact that with the former class the hoods are much more efficient: as regards the latter, when the single components of the convertible anastigmat are employed it is nearly always the front lens that is removed, and thus the mount of the lens serves as a highly efficient hood for the back glass.

Camera Copies.

The recent installation of the Photostat Patent Office brings forward the subject of quick and cheap copying of documents, printed matter, or drawings, by means of the camera. As most of our readers are aware in this and similar apparatus, the print is made by exposing bromide paper in a special camera which is scaled to various sizes. The image is normally a negative one, although positives may be made by recopying them same size. Taken in an ordinary camera the images would be laterally inverted, but this can be obviated by fitting a reversing prism or mirror to the lens, the latter being, of course, much the cheaper arrangement. We think that photographers who work for engineering and other manufacturing firms would do well to take this class of work into consideration, as it would secure many orders for copies of drawings, plans, etc., not amenable to duplication by the usual heliographic methods, which call for a translucent original. It should not be difficult to arrange an attachment to any ordinary large camera for moderate-sized subjects, while larger ones could be managed by taking a small negative and enlarging in the usual way. We have seen some excellent copies up to three feet across made in this way and as the work practically mechanical, highly-skilled labour is not necessary. On point is essential, and that is that the same lens should be used both for making the negative and the enlargement. The operation has been very successfully carried out thus: supposing an architect's drawing has to be reproduced, a copy is made upon a process-plate, say, half-plate or whole-plate size, the distances between lens and original and lens and plate being accurately measured. The lens is then transferred to the enlarger, and the negative and bromide paper carefully placed at exactly the same distances, the result being a full-sized copy free from any distortion, the image having been made to travel back through the same optical system by which it was produced. Where much work has to be done it would be well to have both camera and enlarger rigidly set to the required points so that for full-sized reproductions no setting would be necessary. With a proper artificial lighting scheme the exposures of both plate and enlargement would be a fixed quantity, and a spoiled sheet almost unknown.

The Shop Window.

A few days ago we were asked whether it was advisable to retain a shop window for the display of specimens or to be satisfied with show-cases in a lobby and let off the shop. This is not quite such a simple question to answer as it appears at first sight, since many factors have to be taken into consideration. The first of these is the class of business which is intended to be done. The highest class of portraitists depends almost entirely upon introductions and to a lesser degree upon reproductions of their pictures in the press. Some go no farther than a brass door-plate to advertise their locale, a few even dispense with this, while others have modest show-cases with only one or two specimens on view at a tine. A few of the older firms have large lobby shows or shop windows, but it is not until we reach those who cater mainly for chance trade that we find the window show really popular. Recently there has been a great increase in these window shows in London and other large centres, so that we must conclude that they have been found to be a paying proposition. It may be noted that many of the large portrait shops are being run by people who are also engaged in other branches of industry, and they have treated photographs in the same way as they would clothes, jewelers, or tobacco. Surely, therefore, it is quite in order for the photographer, pure and simple, to take a leaf from the business man's book and to go in for bold advertisement, providing that he has the means to do it properly, and not to lose sight of the next important factor in the matter that of locality. To be effective a window display must be situated where there is a considerable amount of traffic, and in what may be called a shopping or market thoroughfare, where there are other attractions. Even in the same street one position is valuable and another almost worthless. In nearly every important thoroughfare there is one side which is much better for business than the other, and this keen business man is careful to ascertain before he invests his money.

Photography's War Work

[The immense part played by aerial photography in the prosecution of the war is naturally realized by photographers, a very large number of whom have been practically engaged in carrying it on. But perhaps the magnitude of the scale is not a matter of common knowledge, and therefore we embrace the opportunity of reprinting from the "Daily Telegraph" of Monday last an article which presumably embodies official figures. It is interesting to find that in the essential matters of cameras and lenses the British forces were better equipped than the German. The fact has recently been the subject of remark as regards lenses, and the writer of the 2 notes printed below describes, it will be noticed, the same superiority in respect to cameras. Eds. "B. J."]

           When hostilities broke out in 1914 aerial photography was still in its primitive and experimental stage. A considerable amount of pioneer work had been done both from balloons and aero planes; a small but valuable literature was arising; but the impetus of war was required, with the aid of the immense scientific and technical resources behind the Royal Air Force, to exploit its possibilities. Some idea of the progress made can be gained from the fact that on the Western front alone during the last ten months of war no tower than 264,605 Royal Air Force negatives were taken in the air over German territory, and the gigantic total of 5,800,000 prints was made from these negatives for the use of the Intelligence Staff.
           The most recent types of Royal Air Force cameras are very highly finished pieces of work. .The lens itself is shielded in a deep tube which faces vertically downwards, thus preventing direct sunlight falling upon it. At the other end of the camera is a steel chamber, containing the automatic device for changing the plates after each exposure. The entire apparatus is securely fastened to the side of the machine, and u connected by a wire with the observer's seat. The pressure of a lever is sufficient to expose a plate and to bring a new plate into position. The German cameras, as recently exhibited in the Strand, lack many of the exquisite mechanical refinements of the British instrument, particularly the ingenious device by which the plates are automatically changed in the air, without any attention whatever from the pilot. This striking British invention ha enabled many excellent and valuable photographs to be taken while the machine itself has been under heavy fire both from the air and the ground.

High-Speed Photography.

           Anyone who has tried to take a snapshot from the carriage window of an express train realizes the difficulty experienced in obtaining a negative entirely free from movement. The same difficulties are, of coarse, experienced in taking photographs from the air. A modern aero plane is really a traveling observation platform moving at from fifty to a hundred miles an hour. As the pace of the machine cannot be altered, the object to be taken must be "snapped" as it slips swiftly by beneath the machine. Aerial photography is, therefore, high-speed photography of a special kind. An aerial photograph is almost always under-exposed, and this calls for exceptional treatment when the plates come to be developed. Apart from this peculiarity, however, it is the definite policy of the Royal Air Force to specialize in very thin negatives. A dense negative takes far too long to print by artificial light. A thin negative enables prints to be made in about three seconds. In this way a trained Royal Air Force photographer can print and develop as many as eighty separate enlargements in the course of an hour.
           For this scientific work the Royal Air Force has trained large numbers of highly skilled workers. In the model dark-rooms at the Central School of Aerial Photography every candidate for acceptance as a R.A.F. photographer must first pass a severe test, designed to reveal his suitability or otherwise for the work. He is then given a month's practical intensive training, particular attention being paid to the processes of development, and to the enlargement of negatives by artificial light. Much importance is attached to the rapidity with which these enlargements ran be produced, for the fate of a battle may depend upon the promptness with which large scale copies of a vital subject can be supplied to the Intelligence Staff. After a further course at a training centre in England, the airman-photographer would proceed to a service squadron overseas and be assigned to a photographic section working with a recon naissance Bight. Such a "section" usually consists of a technical non-commissioned officer and about seven men, who take in torus the more confined and laborious aspects of the work. One man will “load” the magazines with unexposed plates, another will fix the cameras to the machines prior to flight, and receive them on return; others are detailed for developing, washing, drying, and plotting the negatives. Several men are constantly engaged in tin enlarging room, exposing and developing as many as 100 prints in an hour.

Before an Offensive.

           It is during the strenuous days preceding a big offensive that photographic activity raises to its maximum. During the successive big drives made by the British in France during the summer and autumn of last year, the entire field of operations was photographed over and over again. If a new series of enemy trenches were constructed during the night, a R.A.F. reconnaissance squadron would bring home photographic evidence of the fact on the following morning. It was no uncommon thing for as many as 11,000 negatives to be made on the Western front alone during a single week preceding an important advance.
           In addition to this vast work of aerial reconnaissance, photography was also extensively used for verifying the results of artillery fire, and for recording the precise effects of bombs dropped from the sir. The very Inking photographs of Frankfort, Mannheim, Mets, Sablon, etc., recently published in the Press, were actually taken during the raids upon those towns. Another valuable development was the application of the stereoscope to war intelligence. By taking two photographs of the same object, say an enemy trench system, at an interval of a few seconds, a striking stereoscopic effect is obtained which throws all the ramparts and other elevated portions of the enemy work into high relief. In this way the principal difficulties to be encountered by the attacking party can be foreseen.
           Aerial photography is destined to become one of the big new industries of the future. The topographical surveys of to-morrow will be photographic surveys; the school and commercial atlases will be photographic atlases. Exploration, commerce, scientific research must all benefit by an industry which may well grow to very largo proportions. In this field of post-war industrial activity, Britain will inevitably take a foremost place, for she already has at her command in Royal Air Force personnel some of the most highly trained specialist photographers in the world.

Practicus In The Studio: Backgrounds

           The modern photographer regards the background of a picture in a very different light from his predecessor of twenty, or even ten, years ago. Then it was the custom to use elaborately painted scenes, which were supposed to be more or lees suited to the social standing of the sitter. Usually they were highly incongruous, and we often found such combinations as a butcher-boy in a tropical conservatory or a lady in evening dress waiting by the banks of bonnie Loch Lomond. I well remember one enterprising firm who went so far as to have the entrance to Hyde Park accurately reproduced with real posts and rails for church parade sitters, and an interior of one of the salons in Buckingham Palace for court dresses. This sort of thing was borrowed from a certain school of portrait painters who considered it necessary to depict their models in what they considered an appropriate entourage. Fortunately we have changed all that, and the scenic background is rarely used except in the "while-you-wait" studio, where it serves to cover up finger-prints and stress markings in other words, it has almost entirely "retired into the background." The painter had one reason for introducing scenic effects into his pictures which does not apply to photography, for his subject being fully coloured often called for a foil, a warm-toned curtain, or sometimes even a conflagration, as in some naval or military portraits being used to modify a rubicund complexion, while a delicate sky or light foliage served to enhance the charms of a blonde beauty.
           The modern photographer has evidently taken a lesson from stage lighting, in which a concentrated light is often thrown upon the principal character, while the garish colours of the scenery are allowed to remain in semi-obscurity; and this has been all to the good as far as the artistic nature of the result is concerned. Many photographers now confine themselves to plain backgrounds. It is a safe course, although one sometime, (eels that a little relief would often be acceptable, especially for half and full length poses. Hence a dark cloud or suggestion of foliage is often useful, as it allows the figure to show more relief by opposing a light portion to the shadow side of the sitter. There is one disadvantage in using this class of background because it is not always possible to bring the light patch into the desired position. This was overcome by a device, little known in this country, which consisted in having the background made in an endless belt running over two rollers, something like a roller towel, by which the height of any portion of the surface can be adjusted to a nicety. Such a background may carry foliage suggestions, clouds, and plain surfaces in various sections, as the length of 16 ft. affords ample room. Another device for securing gradation was to have the ground made in the form of a shallow saucer, which gave a perfectly natural effect of light and shade just where it was wanted. Such a construction was found in practice to be too unwieldy for general use, and a more convenient way of carrying out the same idea is to have a tall screen made of narrow strips of wood glued to an ordinary plain canvas background of a medium grey tint. This can be placed so as to form a kind of alcove behind the sitter, more or less concavity being given as harder or softer gradation is required, or even be used flat, while when done with it can be rolled up and put in a corner. To make the method of construction quite clear, I will compare it to the roller shutter of a studio dark slide, the wooden slips being, of coarse, turned away from the sitter. Tapestries and curtains form effective backgrounds if judiciously used, but neither the pattern nor the folds should be pronounced in character, only enough being shown to break up the flatness of a plain surface.
           The illumination of the background has an important effect upon its depth of colour, and much may be done by turning it to or from the light, while the distance it is placed under the drawn blinds gives somewhat similar modification. Thus, to obtain the darkest effect from any given tint of grey, we keep it well back from the sitter and bring the edge nearest the side light as far forward as may be, the reverse being done when a lighter tone is required.
           In the case of white backgrounds for "sketch" work it is usually recommended to light these independently by opening the blinds behind the sitter. This is all right in a dull light, but on a bright day the flood of light so projected into the lens is very likely to cause a general fog over the negative. Certainly if the quality of the work is to be considered it is better to secure opacity by Mr. Adamson's method of using red ink and seccotine on the back of the negative. A common error is to paint sketch backgrounds a bluish-white, the idea being that a denser deposit will be obtained. This is quite wrong ; nothing can be whiter than white; the blue only masks any yellow tint in the distemper, and there is no gain by adding it.
           From time to time attempts hare been made to print in backgrounds from film negatives interposed between the portrait negative or to put in backgrounds on the back of the glass. These plans are rarely satisfactory, though in some cases excellent results have been obtained. As a rule, however, the general effect is not so good as from a background which has been photographed with the sitter.
           The materials used for backgrounds are various. For plain tints Melton cloth is excellent when it can be obtained. Failing this, distemper on canvas or stout sheeting is very suitable. For graduated backgrounds distemper may also be used, but it requires a considerable degree of skill to apply it, so that the necessary softness is obtained, and for this class I therefore prefer flatted oil-colour, which does not alter in depth upon drying, and which can be easily worked and softened while wet. Aerograph work upon a plain grey distemper foundation answers very well, but it takes some time to cover so large a space. The aerograph is also excellent for subduing contrast in scenic backgrounds which are too contrasty. I have also improved such by rubbing on black chalk powder exactly in the same way as in finishing an enlargement, but care must be taken to avoid patchiness if there are decided brush marks on the surface. For small grounds up to 54 in. wide dark green or red serge is very good, and a little light may be introduced by dusting powdered French chalk on where required. This is easily removed with a clothes-brush if the plain surface is again required. If you wish to distemper your own backgrounds it is better to purchase one of the many ready-made distempers or to use the Kalko powders (Vanguard Co.). which are specially prepared for this work. Oil-colours should not be purchased ready mixed; they should be procured "ground in oil" in a stiff paste, and this should be thinned down with turpentine or on of the current "turpentine substitutes."
           Lincrusta and Anaglypta are useful for making imitation panelled backgrounds. The latter, being a kind of embossed papier mache, is the cheaper, but will not stand knocking it so well as the Lincrusta does.
           Now that we do not require so many backgrounds the old-fashioned multiple stand should be discarded and the material should be stretched upon light wooden frames fixed upon feet with castors, so that they may be moved about the studio easily and used at either end or diagonally, as may be desired. It is a good plan to have the ends of the studio finished so that they may be used as backgrounds. This has also the excellent fleet of preventing the space behind the movable screens being used as a receptacle for lumber. The oak paneling comes in very well for this, and if the entire end be covered a large group can be accommodated without having to eke out the ordinary-sized ground with curtains, side slips, and other make-shifts.
           As a guide to those who are attempting to make or renovate their own backgrounds for the first time, I give the following hints. Do not expect to get an even surface with one coat of distemper. You may do so but, if not, do not be discouraged, apply a second coat rather thinner in consistency. If working on new canvas or sheeting it is a good plan to give a first coat or filling of thin size, or even starch or flour-paste. Tins prevent the distemper from being sucked into the material, and makes it easier to apply. For oil colour, ordinary glue size is to be preferred. A large paint brush, about three inches across, is easier for the amateur to manage than the orthodox distemper brush, and should always be used for oil. Work quietly, and do not slop on too much colour at once. A good grey can be made by mixing a little Venetian Bed and blue with the black and white. This looks warmer, and photographs better than black and white alone. Remember that distemper dries many shades darker than it appears when wet; therefore before using your mixed colour try a patch' on brown paper and dry it before the fire: you will then know what your background will look like when dry. A very little white will turn black into a light grey. Do not buy black in a dry powder, as it is very difficult to mix; ask for black ground in water. Always strain your distemper through muslin before using, or eke you will get streaks which are caused by unmixed particles of colour which break up under the brush.
           There is a right and a wrong way of nailing a background on to its frame. The wrong way is to fasten all four corners and then to go round the sides. The right way is to drive a strong tack in the middle of the top edge, then to pull the canvas as tightly as possible and drive another tack in the middle of the bottom; then fasten the two sides in the same way. Having got a straight pull these two ways, begin driving in tacks about one and a-half inches apart towards the corners, always working from the centre. In this way any fulness is drawn out as you go on, and the background will be perfectly flat and free from wrinkles. It is a good plan to fasten a loop handle tit iron or brass at each side of the frame; this obviates the necessity of handling the edge of the wood, and keeps the background in much bettor condition. If the frame is wider than you can stretch, a loop of webbing or cord, about eighteen inches long, should be fastened to one of the handles. Holding this and one handle, you can easily move an eight-foot frame single-handed, although if good castors are fitted it may not be necessary to lift it very often.

PRACTICUS.

Carbon Printing By Artificial Light

           Although many photographers, both professional and amateur will be familiar with the fact that the printing of carbon tissue can be done conveniently with the stronger sources of artificial light, such as the electric arc and mercury vapour lamp, as well as by daylight, it does not appear to be so well known that by choosing a suitable source of light prints without the usual lateral inversion can be obtained from ordinary glass-plate negatives by the process of single transfer only. A few remarks on the method of obtaining such prints may therefore be of interest to those who have the necessary facilities in their studios or homes.
           To obtain the unreversed print the tissue most be placed in contact with the plain glass side of the negative, the latter being placed in the printing frame with the film towards the light. The negative moat then be illuminated by a very small but sufficiently actinic sources, and care must be taken that as little light as possible, other than the direct rays from the direct rays from the source, falls on the plate during the exposure.
           The most convenient and satisfactory illuminant is undoubtedly the comparatively new Ediswan "Pointolite" lamp. The actual source in this lamp is a small metal ball, the diameter of which is about two millimeters, supported in the centre of a glass bulb, some 10 centimeters in diameter. The ball is rendered incandescent by a small electric arc, which obtained by placing a second electrode immediately over the ball. The usual rating is 100 candle-power, and the current required about 1,5 amperes. This intense and practically “point” source of light is highly actinic, and forms an ideal illuminant for many optical purposes. In using the lamp for the purpose under consideration it is well to place the negative end of box coated inside with a dead black, and to the lamp outside the box at the other end. A small rectangular hole is to be provided in thia end, so that when the lamp u placed as close as possible to the hole the beam of light which enters the box will just cover the film of the negative. The distance between the centre of the bulb and the negative may be 20 centimeters, or even less. It is clear that a number of negatives may be printed at the same time, the bulb of the lamp being placed for this purpose in the middle of a circular or, say, octagonal box with suitable radial partitions; light reflected from the film of one negative must not be allowed to fall on the others. When six negatives are printed at once the cost of printing may be less than that of the final rapport used in the double transfer process, and there is, of course, also a considerable saving of time. With negatives of average density the time of exposure required is 40 to 50 minutes. The time may be shortened, if fine definition is not required, by reducing the distance between the negative and the lamp. It may be added that the "Pointolite" takes so little current that is may be connected to any lamp-holder, special wiring not being required.
           A second illuminant which will be found to give satisfactory results is the iron arc, but this can only be used where ordinary arc lights are installed or where the electrical fittings allow the use of a current of 5 or 6 amperes. The advantage of an arc with iron pole, instead of the usual carbon poles is that the iron burns away very slowly, so that no “feed” is required. In fact, the lamp in this case may consist simply of two iron rods, 1 or 1*(1/2) cm. in thickness supported in the same vertical line with a space of about 4 mm. between their nearer ends. The poles must be, of course, insulated and connected to the mains in the same manner as the ordinary arc lamp. The arc is most conveniently “struck” by drawing a third iron rod across the ends of the pole piece. Once the pole, become hot the lamp will run for long periods, sometimes hours, without requiring attention. If the power is supplied by direct current the upper pole should be made the negative one. It is well to place a tray containing .water below the lamp, as occasionally small pieces of molten iron may fall. As the light is very rich in ultraviolet rays it should not be used except when the eyes are protected by plain glass or ordinary spectacles. With this more powerful source a larger number of prints may be exposed at once, the frames being arranged in a circle, say 50 cm. from the light. At this distance no special screens are necessary and reflection from surrounding objects is of no account unless they are light-coloured. The exposure required at 50 cm. is about 20 minutes, with a current of amperes.
           With the distances quoted above the diameter of the circle of confusion representing the points of the image is about .005 mm, but there is a slight loss of definition which appears to be due to reflection between the front and back surfaces of the negative. The want of sharpness, however, is remarkably slight, and in most cases amounts to no more than a softening of the otherwise hard lines of the picture, an effect which in many subjects is quite pleasing.

S. S. RICHARDSON.

Re-Sittings

           The question of re-sittings is one which perennially crops up, although we do not think that photographers have so much to complain of in these days as they had a few years ago. Probably the broader style of treatment which is now general has a good deal to do with it, while more intelligent and less mechanical retouching has also had an effect. Still, they are common enough to be reckoned one of the plagues of professional photography, and we have to consider the best way to deal with them.
           In the first place, the operator will save himself much heartburning if he can bring himself to realize that the sitter does not usually intend to cast any imputation upon his ability. The old hand knows this, but the young artist is apt to take the return of proofs with perhaps rather a pointed remark or two as a sort of blow in the face, and either to contest the matter or to yield with, rather a bad grace. That is quite the wrong thing to do. He should endeavour to see the matter from the sitter's point of view as well as from his own, and to do all that he can to give satisfaction. Personal recommendations are the best possible advertisements for any business, and a dissatisfied client will often be the means of diverting many profitable orders, while the assurance that polite and considerate treatment can always be expected will have the contrary effect. There are few people whose genius is so transcendent that they can afford to be ungracious, not to say rude, so that our advice is to stifle one's feelings and to accept an unpleasant situation with a smile. There are, of course, exceptions to this rule, and if the photographer can see that an attempt is being made to impose upon him there are good grounds for protecting himself against it.
           It is not wise to mention the subject or to make any conditions as to re-sittings on any price list or even verbally at the time of sitting, as this shows a lack of confidence. If re-sittings are so frequent as to be a serious matter it is a sign that there is something wrong with the work, and a decided attempt should be made to remedy it. In many cases faulty or excessive retouching is to blame, and in others a want of attention to small details in drew or posing. Therefore, in every case it should be ascertained what the fault is before proceeding with the second sitting.
           Various plans have been tried for avoiding loss in this way, but moat of them are open to objection. One is to make a charge if any alteration is made in the dress or style of hairdressing. This appears fair at first sight, but it puts an unpleasant restraint upon the sitter, who may have good reason for complaint, and who can see that certain modifications would help to secure the desired result. Another method is to charge a moderate fee for the sitting and a set of proofs, after which copies may be ordered at a fixed price each. This has its advantages, but as a rule if the proofs are not quite satisfactory the sitter does not return, but tries another studio, so that it is a question of half a guinea sitting fee and no further order or a two or three guinea order with a possibility of a remitting at a cost of two or three plates, with perhaps an additional order at the end. In many studios it is the custom to destroy negatives which are not at once approved of, and if the sitter does not wish thin to be done large a registration fee of, say, half a crown if they are to be kept. Occasionally a sitter will ask for this to be done, in case the second sitting is no more satisfactory than the first. It may be worth while to adopt this plan, but seems to us that the fewer conditions imposed in an intimate business like portraiture the better.
           After all prevention is better than cure, and every step should be taken to avoid the necessity rather than to remedy it when it comes. In the first place, we must remember that the average sitter has no clear idea of the powers of the retoucher, therefore rough proofs should never be submitted unless the negatives are really good and require but little work upon them. It is difficult to explain that this can be altered and that can be altered; the sitter is not so sure about it, and presses for a re-sitting which would not have been asked for if the alterations had been made before proofing. We have noticed that those portraitists who do most of the work themselves are less troubled than the large businesses where it is carried on more or less a factory system.
           Another point is that sufficient choice of poses should be offered to the sitter. One of the most successful businesses has been built up on the principle of submitting six proofs for an average order. Some people have called this taking your re-sittings beforehand, but it is eminently sensible not only as helping to avoid a second trial, but because with so many positions to choose from the original order is in very many cases increased so that on the whole the additional outlay brings in a good profit. At the present price of plates this may not be regarded as advisable, but there is a wide margin between six proofs and the two which are often submitted.
           Whenever it is possible the granting of a re-sitting should be done by the operator and not by the receptionist. The latter may be an excellent business woman tactful obliging but she has rarely the artistic or technical knowledge which are necessary to decide the point. Moreover the sitter enters the studio with less diffidence if the question has been settled wife the person whom she considers is in fault. It should hardly be necessary to say that no proofs with which the photographer himself is not satisfied should be sent oat without remark. In such cases it is well worth offering re-sitting at once. It may not always be accepted, but if it is the sitter comes back in a pleasant mood, which is decidedly helpful. All this is an old story to those who have spent many years in studio work, but we hope that it will go some way to smooth over a disagreeable side of life to those who are still young at it. In every walk of life we are open to criticism, and photographers should be thankful that they are not politicians whose incompetence we see denounced every time we open a newspaper.

EX CATHEDRA: Continuation

Dark-Room Lighting.

           We recently were in the dark-room of a photographic friend whose amateur experience in electric wiring and battery making had been apphed in the provision of what he regarded as luxuries in the way of illumination. We are not so sure but that for a commercial dark-room, there were little more than the necessities for minimizing waste of labour. We should explain that our friend's dark-room, which was of ample size, and had the customary developing bench in one corner, had cupboards the contents of which were clearly seen by means of a little yellow electric bulb worked from a battery and connected to the latter so that the opening of the door completed the electric circuit whilst its closing the light off again. In many commercial dark-rooms where from lack of space elsewhere things are kept which are not needed in development operations a device of this kind would often save the time of a second assistant who might be wanting them whilst the dark-room was in use. Naturally enough our friend's room was fitted with two types of lamp, one with the safe-light nearly vertical the examination of negatives, and another of the horizontal pattern for use in the development of prints. Another fixture, and one which we have regularly used our self, is a ceiling light consisting of a fairly large lamp I a foot or so from the ceiling with its safe-light uppermost. The illumination, after its reflection from the ceiling provides a weak, but safe, and very comfortable light throughout the room.

Passe-Partouts.

           The passé-partout method of framing may very reasonably be thought to be one which will retain its popularity - certainly among amateur photographers and, no doubt, among the customers of professionals, to whom, however, it has not been offered as freely as its artistic possibilities warrant. It is sometimes astonishing to us to notice the ugly designs of frames which are shown in the show windows of photographers whose taste, judging from their own work in portraiture, might be thought to be a good deal better. The passe-partout with its ready adaptability to the key and colour of the print is particularly fitted for the display of window specimens, and, a* we have said, might well be offered to the customers of a studio more than it has been. Perhaps the manufacturers may do something towards further popularizing this form of framing; the altogether charming metal edging which for some year or two now has been on the market is one way of overcoming an objection to the passe-partout, viz., the impermanence of its paper binding. Messrs. Butcher have done something in the same direction by providing the slender frames, which are practically more or less solid surrounds for passe-partouts. More might certainly be done in this way by providing in one form or another a frame for the passe-partout which need only be of the lightest construction, any hanging tabs or rings ere attached to the back of the passe-partout itself, and the accessory frame thus relieved of any weight.

Fastest Fixing.

           Among other suggestions which we recently made to a correspondent who sent up a batch of stained paper natives was that of using a bath of the maximum fixing speed. Where, as in the case of such negatives, the process of fixing cannot be seen by the eye it is more than ordinarily necessary to arrange matters so as to secure complete fixation. As was ascertained some years ago by Mr. Welborne Piper in the course of a lengthy series of experiments, a fixing bath of 40 per cent, strength, that is to say, 8 ozs. dissolved, water to make 20 ozs. of solution, fixes more rapidly than any which is weaker or stronger. Although these experiments were made with a particular emulsion, our own experience with plates of many different makes has shown us that for practical purposes the strength of bath abovementioned may be taken as that which fixes in the shortest time. Obviously more hypo is required to make up a. bath of this strength, but, setting aside loss from sheer carelessness, such as splashing the solution about, there is no reason to believe that a bath of this strength is any less economical in use than one containing, say, only 4 to 6 ozs. in a pint of water. We have yet to find a plate with which a bath of this maximum strength cannot be used. In the case of papers it may easily happen that frilling or blisters may arise from the use of a fixing bath of this strength, although in our experience such effects have been very rare.

An Enlargement Attachment.

           By those photographers who require to make an enlargement only on comparatively rare occasions the studio camera may be very suitably employed. The addition of a small attachment serves to convert it into an enlarger capable of making a print of the size of the largest plate which the camera will take. The attachment consists simply of a box mounted to slide, by means of a panel, in the grooves which carry the camera lens. The box is provided at one end for the reception of the negative to be enlarged and at the other with an R.R. lens of focus suitable for the purpose. The distance between the diaphragm of the lens and the negative will naturally be adjusted in correspondence with the degree of enlargement required. For this there is the very simple rule that the distance will be one focal length plus one-half one-third, one-fourth, according as the enlargement is to I three or four times. Where the studio does not provide a ready outlook to a clear sky for the illumination of the negatives, the necessity of tilting the camera may be avoided by using a reflector in the shape of a mirror or even a white card placed at an angle of 45 to the plane of the negative. An alternative where electric light it used in the studio may consist simply in placing this reflector, or rather the white card, a few inches below an, arc lamp or a half-watt bulb.

PRACTICUS IN THE STUDIO: MANAGING THE SITTER

           The first stop towards managing your sitter is to hare perfect control of your own feelings; no matter what worries or annoyances yon hare to encounter, do not take them into the studio with yon. Man is an imitative animal, and in the great majority of cases unconsciously copies the temperament of those surrounding him in a greater or lees degree, according to his own strength of character. Therefore, it is very necessary that the photographer should cultivate a quiet geniality of manner, adapting his degree of freedom of speech and manner to that of his sitters, taking care to avoid an excess of familiarity with those who bare an idea of their own importance or a patronizing air with those of more modest manners. To pat it briefly, the operator must be "all things men" (and women), and should boar in mind that "As iron sharpeneth iron so is a man's face brightened by the countenance of his friend."
           One person at a time is quite enough to manage, and any friends who accompany the sitter most not be allowed to remain in the studio while the kitting is made. If possible they should be induced to remain in the reception-room, but usually it will not be easy to arrange thin, and one at least will be allowed to enter toe studio. I have always made a rule of having a screened-off corner with comfortable chair, to which I escort the friend as soon as I have welcomed the sitter taking rare that the friend cannot peep out and he seen just as an exposure is being made. There is a goal reason for this; it prevents the friend from criticizing the pose, seen from a totally different position from the camera, id also prevents conversation, which often results in giggling With children, it is, of course, necessary that they should he accompanied by an adult, but only one should be allowed. If a mother and nurse come, try to get the mother to retire behind the screen, as the child will usually behave better with the nurse, who will not try to excite it. A whole family party in the studio usually means a resitting after a lot of valuable time and plates have been wasted. Even if a family group has been taken, the members should be shown out if separate sittings of any of the children are required, and it is sometimes politic to ask permission to make a negative or two of a pretty youngster, even if not ordered. The parents feel flattered by the compliment, and go away feeling that the photographer m really a man of taste.
           We now come to the practical work of making the portrait, some people call it a "picture," and we should endeavour to make it worthy of both designations. To this end it is necessary to make a rapid survey of the sitter's features and figure so as to get the best result possible. It is said that Reynolds always wanted to dine with a person before he painted his portrait, so as to get a true impression of his appearance, but the photographer is not so fortunate, for he has only a minute or two to decide upon his course of action. I will endeavour to indicate a few of the points to be observed. There is not one person in a hundred whose features are even approximately symmetrical, so that it is necessary first to decide which side of the face is to be turned to the light. The nose will often appear quite straight if the head be turned one way, and either aquiline or retrousse if turned the other. As a rule it is advisable to choose the straight side unless other conditions militate, in which case the aid of the retoucher must be sought. With nine people out of ten the left side of the face is the most perfect, so that the studio should be arranged to take negatives with the light falling on the sitter's left hand.
           The eyes are usually uneven in size and sometimes in height; the best result can be obtained by having the larger or higher eye nearest to the camera. In cases of a decided squint the abnormal eye should be turned from the camera and brought well into shade, so that it can be more easily corrected in the retouching. If the profile is fairly good, one or two positions of it should be taken - when the sitter is afflicted in this way.
           If the sitter's neck be short it can be made the most of by lowering the camera considerably, while with a long, scraggy neck the camera should be well raised. The height of the camera has an important effect upon the rendering of the nose. A long nose is shortened and the upper lip well shown with a low camera, while a snub nose and long upper lip is better rendered from a higher position. Tilting the head up or down will give the same effect, but this would interfere with the pose of the head and probably spoil the eyes and forehead. A small, receding forehead should be inclined towards the camera, while the possessor of a massive one may throw the head well back. In both these cases the pose will probably be a natural one to the sitter.
           The hands are a constant source of worry, and many photographers now look the difficulty boldly in the face and take bust portraits almost exclusively. If they have to be included in the picture the hands should be made as unobtrusive as possible, and care should be taken not to let them come too far forward, or they will appear larger than they really are. It is usually recommended to use the swing back to bring the hands into focus without stopping down the lens, but this is not a good plan, as it necessarily renders them on a larger scale than the rest of the picture. It is always desirable to use as long focus a lens as possible for sitting figures, so as to minimize distortion of this kind. Of course, some sitters have small hands, and then there is little difficulty in dealing with them. One position is always to be avoided, that of having the fingers interlaced while the hands are lying on the knees. A book or flower may be held so as partly to hide the hands, but this device is rather hackneyed. A long chain or string of beads falling from the neck into the lap often affords an opportunity for a graceful arrangement of the fingers.
           Full-length portraits are now rarely taken unless for the express purpose of displaying the dress or uniform. For these the camera should be raised, so that the lens is about level with the breast of the sitter say, five or six inches below the chin. Care should be taken that the body is well balanced upon the feet, which should not be placed evenly, but one; little before the other; in military terms, the sitter should ''stand at ease" and not at "attention." At the risk of being considered old-fashioned I strongly advocate the judicious use of the head-rest for standing figures, as not only are "moves" reduced to a minimum, but it prevents the sitter from dropping into a slouching position. I prefer not to place the rest behind the head, but behind one shoulder.
           The rest is also very useful when making dancing poses, as it enables a position to be held with one foot in the air. The ironwork should be painted a fairly light grey, so that it is lost in the background and is easy to work out on the negative. If black or dark green, as usually supplied, it is difficult to get rid of.
           Young children present a different set of problems from adult sitters. Their features do not require so much consideration, and the lighting is usually full. The great points are to keep them still and to secure a happy expression. They should not be allowed to curl themselves up with one or both legs drawn up under them, but otherwise they will find their own poses, from which the photographer should make his choice. The great thing is to get the child's confidence as soon as it comes into the studio, and to keep the camera out of evidence as much as possible. To attempt to work with children as one would with adults is to court failure. Many of my best child pictures have bean obtained by focusing upon a cushion or similar article, placed where it is intended the child to be, before it came into the studio at all ; then the plate was inserted t the slide drawn, and the child coaxed into position in an innocent sort of way. Then the exposure was made, using a rather long release tube or cable, and while the child's attention was otherwise occupied the plate changed and the process repeated. A little table at which the child can stand is an excellent accessory, as if a toy be placed upon it in focus the child will usually go to it of its own accord; if spoken to it will usually look up with a pleased expression, and the exposure is instantly made. I generally find that I can get three sharp negatives out of four exposures when working this way. The "little bird" trick is not a bad one; but there should be no deception, the bird should be forthcoming. I have made hundreds of negatives with the help of a cheap toy, consisting of a small metal bird perched on a bulb which contained a water warbler, worked by a rubber tube. The bird flapped his wings and opened his beak while singing. The plan was to tell the child to look for the bird, and to give a note or two on the warbler, and immediately after the exposure to show the bird in action for a few seconds. It was then hidden and the child told that it would come back if he were good. Alas! a little sitter found it when I was not looking, and effectually ended its career. It was probably of Hun origin, and, I hope, cannot be replaced. However, the idea remains, and it might be possible to make a substitute. It is a good plan to keep a few cheap toys so that a child can take one away with it, especially if a resitting may be necessary, as the child will be willing to pay another visit to a place where toys are given away. Big toys, such as Teddy bears, horses, etc., are a nuisance, and the toy should be used to attract the child's attention and not given to it until the exposure is made. Before I learned this I have had a child marches away with it into a dark corner and sit down to play with it, any attempt to entice it out being hopeless. I have said nothing about posing either adults or children, as little useful information can be conveyed by words. By the study of paintings, engravings, and the work of good photographers much can 'be learned and a general idea of what is graceful and artistic obtained, then when the sitter arrives one is not at a loss for a pose. If there is any characteristic mannerism about the sitter it should be preserved; if a man habitually holds his head on one side it is a mistake to put it straight, as it would be to make a man who stoops slightly stand bolt upright.

UTILITARIAN STEREOPHOTOGRAPHY

           To the great majority of people the stereoscope is nothing more than a scientific toy or perhaps a rather troublesome means of looking at a number of photographs which have cost more than usual labour to produce. In consequence the instrument has been banished from its place in the drawing-room, and only a few enthusiasts who make their own slides venture to keep it in evidence. We have from time to time urged the claim of stereoscopy o be the one branch of photography with which the draughtsman or painter cannot compete, and, further, we have pointed out the great educational value of such pictures, which are as near faithful renderings of their subjects as it is possible to obtain upon a flat surface. When produced in an additive colour process such as that of F. E. Ives, and shown on a binocular Kromskop the illusion is almost perfect.
           For the moment we are not concerned with the beauty or scientific interest of stereoscopic work so much as with its utility in various branches of science and industry. There are many subjects full of intricate detail lying in several planes which cannot be rendered satisfactorily in a monocular photograph or by the cleverest artist. In the one case we have a plan with a certain amount of shading to represent relief and in the other we get the impression of one person who if not an expert in the subject may omit important data, while if he is an expert may unconsciously emphasize such features as seem important to him. The stereoscope is impartial in such matters, and if the separation of the view-points for the two negatives has been properly adjusted the subject should appear exactly as in nature.
           It is not necessary to give a detailed list of subjects suitable for stereoscopy, for once the question is raised any intelligent person will readily perceive in what way he can apply it to further his own work or studies. Recently we were glad to hear that the medical profession has shown considerable interest in this work. Many valuable records have been obtained, but there are still many branches of science and art in which development is possible. For example, crystalline fractures such as those of cast-iron or brass, can be photographed on an enlarged scale, and by a judicious separation of the lenses any desired amount of relief can be obtained. As this question of separation has not always been clearly understood, it may be well to point out that the degree of relief obtained is governed entirely by the separation between the lenses when the exposure is made. If only one lens be used and the exposures made successively, then the separation is the distance the lens has been moved. The distance by which the centres of prints is separated has no effect on the relief but only upon the ease with which they are combined in the stereoscope. Much of the eye strain which many people experienced is due to the separation in this respect being too great.
           The error that is most likely to be made is that of using too wide a separation when working at close quarters, as when taking small objects on full or even quarter scale and in portraiture or ethnographical studies. The usual focal length of lenses supplied in pairs for stereoscopic work varies from three to six inches. Occasionally lengths up to eight inches are supplied, but this is unusual, except to special order. Even this is insufficient for close up work, as it will readily be understood that at a working distance of eighteen inches the disparity of the view-points of two lenses with a separation of three inches is very considerable, giving a drawn-
out appearance to any projecting details. For example, if we desired to take a stereograph of a lump of sugar, we should obtain quite a false rendering of the crystalline texture, the small crystals being drawn out into needlelike forms. It is, therefore, often desirable to avoid the use of paired lenses, and to make the exposures by successively moving the camera the necessary distance.
           It will thus be teen that for stereographs of immobile subject, the possessor of a small camera needs no additional apparatus. All that is needed is a small board or platform on which the camera can be slidden laterally and secured at the proper point. Small deviors for this purpose are listed by most of the principal dealers, and can, we believe, still be supplied. An appliance which should prove of great value to the scientific photographer is the double mirror, introduced by Mr. Theodore Brown. In this apparatus two small mirror are hinged together like a book so that they may be placed either in one plane or at any angle to each other. When inclined together, be it ever so slightly, a dissimilar view of any object is reflected by each, and if these are photographed with an ordinary single-lens camera we have at one exposure a stereoscopic negative, no central partition or other modification of the apparatus being necessary. Although introduced mainly as a cheap and simple means of making stereo-negatives, the Brown transmitter possesses many great advantages. In the first place the limit as to the diameter of the lens is removed. Thus, rapid portrait lenses or large aperture anastigmats of any desired focal length may be used, and in the case of surgical work the simultaneous exposure minimises the risk of movement. A few experiments will be necessary to find the degree of inclination necessary for various distances, and if the mounting included a graduated arc such as is fitted to binocular field glasses, this could be registered for future use. There is one slight drawback to this method of working, and that is the fact that the images are laterally inverted, but for scientific work this would in many cases of no moment; if it were the prints can be made by a transfer process such as Transferotype or the single transfer carbon process or, if films are used, by printing from the reverse side. By this method the Datives may be of much larger dimensions than is, possible with a binocular camera even as large as 15 x 12 being practicable. The prints may then be viewed in the stone or reflecting stereoscope instead of the Brewster or box-form of instrument. Stereoscopic prints if not made in the form of transparencies, are best if I on gelatino-chloride paper, as there is less chance of loosing shadow detail than there is with developing papers. The negatives should be thin and fully exposed what would be called flat in ordinary work where the grapher relies only upon light and shade to give a semblance of relief.

EX CATHEDRA

Over-printed self-toning paper.

           With some of the more recent batches of self-toning paper we have noticed a lack of uniformity. One batch that we were using lost very considerably in the fixing-bath, with the result that printing had to be carried much deeper in order to ensure the finished print being of the requisite depth and of a good colour. A later batch, upon fixing the first print or two, showed that it was one in which the prints lost very little, and we at first thought that owing to this difference the whole of the untoned and fixed prints (a very large number) were spoiled through the printing being carried too deeply. They were, however, saved in the following way. A bath containing 4 ozs. common salt in 10 of water was made up and the prints previous to fixing were placed in this for about fifteen minutes. Upon transferring to the ordinary fixing-bath they lost a good deal of depth, being reduced to just the right quality. The tone, of course, was modified, being of a cold black, and equal in every way to platinum-toned P.O. P. In fact, it is so satisfactory that many may decide to finish all their self-toning prints in this way instead of in the ordinary sepia that is so common. We wonder that more users of self-toning paper, and especially the collodion emulsions, do not favour this method more, as it yields prints of delightful richness and quality.

Describing second–hand goods.

           Those who have at any time had occasion to study the second-hand market must have found that many advertisers, both dealers and private individuals, frequently leave much to be desired in describing the goods that are for disposal. Take the case of apparatus with which the general photographer is not very familiar or that of an older pattern not to be found listed in any of the catalogues issued within the last ten years. We recently saw advertised, "A fine half-plate camera by - (naming a maker of a score of years ago), with two slides, no lens." This kind of advertisement, it must be admitted, gives little or no information as to the instrument for disposal, whether it is of single, double, or triple extension, whether it has a turn or tilting table, or a rising front or swing back, details that any practical worker purchasing a camera requires to have for his consideration. An older photographer might know that particular pattern even from the inadequate description giveu, but a modem worker certainly would not unless he happened to have catalogues hand of a score of years back. We have even seen lenses listed by first-class firms with a reputation for second-hand goods from which the aperture, focal length, and other important details were omitted. Advertisers of second-hand photographic apparatus will do well to put themselves in the position of the buyer when drafting out details of their goods, giving just those full details that they themselves would wish to have: a few words should not be omitted if their inclusion would give fulness to the description. It may be that an advertisement giving full information will be seen by a buyer on the look-out for the particular model of the" apparatus described, whereas he would not take the trouble to write to the vendor, if the goods were not fully detailed, for fuller particulars.

Rubber Stamps.

           As a rule a rubber stamp impression upon a mount gives an idea of cheapness, and quite spoils the effect of what might otherwise be an excellent production. This, like many other things, is due to a want of knowledge of the capabilities of our materials. To many people a rubber stamp is oval or circular in. form, the type plain black, and the colour of ink violet, and as far as ordinary office work is concerned these conditions are doubtless satisfactory. It is, however, quite possible to employ rubber stamps in such a way that they may be impressed upon the highest class of mount without being distinguished from lithographic or typographic work. In an instance which recently came under our notice a photographer used a steel die of his signature and town for stamping his mounts or prints. From this he had electros made which were used for printing upon mounts in brown ink. Finding the need for occasionally marking odd mounts and enlargements he sent the original die to a rubber stamp maker and received a rubber facsimile with box, pad and brown ink complete. With this outfit it was possible to sign mounts without causing anything unusual in their appearance. We have also seen the well-known square label form of address, "A portrait from the studio of - ," reproduced in the same way, the result being quite satisfactory. The secret of getting good impressions is to keep the pad and stamp free from dust. An old toothbrush is excellent for keeping the stamp clean, while the pad should be scraped the right way of the material with a blunt knife. When fresh ink is applied it should be well rubbed into the pad and allowed to remain for an hour or so before using. When long narrow stamps have to be used it is a good plan to have a small brass prong projecting from one side of the plate, so as to form two little feet, on which the stamp will stand squarely. These feet also afford a good means of keeping the lettering in correct alignment with the edge of the print.