Low-Priced Trade Work.
In a business such as photography, in which the goods sold to the public exhibit so wide a range of quality, it is, of course, natural to find a similar range of quality in the work done by trade firms for photographers. In both cases the quality is more or less accurately reflected in the price which is charged. A consideration of these facts should, we think, provide tie answer to those who now and again urge upon our publishers that they should exclude the very low-priced firms from our advertising pages. An order for enlargements to one such firm may have been executed in what the disappointed maker of the negatives angrily calls a “disgraceful" style, on the strength of which, and without showing either the enlargements or the negatives supplied for them, it is protested that the firm should not be allowed to advertise its offers of service. As we have said, a complaint of this kind can only be made in the absence of a comparison between the price which has been paid and that charged by firms of the first or even the second grade. Probably the chief difference between low-price and high-price firms - a more essential difference than poorer materials and cheaper labour is that their scale of prices does not allow them to repair defective work by doing it again. They send their first production unless its defects are too gross even for their standard, and hence the result is very largely a matter of chance. Like the little girl and dependent on the negative, it may be very, very good or it may be horrid. If it be the latter, the purchaser must surely think that he could hardly expect anything else at the price. His case is paralleled by that of anyone who puts money in a high-yielding investment: he is buying something cheaply priced, and he takes his chances on it. No doubt the advertiser announces that his work is first-class, but then what advertiser does not?
A Lecture on Photography.
Perhaps it is a welcome sign of greater general interest in technical and scientific matters, perhaps the result of the searchlight prominence of photography in the war, but we have lately received quite a number of requests that we should name the book to be recommended to anyone anxious to deliver a popular lecture on photography. The fitness for his purpose of a would-be lecturer who finds it necessary to put the question may be doubted, but at any rate the inquiry exhibits a praiseworthy desire for information, and doubtless there are many with a thorough practical acquaintance with photography who are not too self-confident to see that much more is demanded of a lecturer on the subject. For such as they a book which provides, a serviceable basis of information is Mr. Chapman Jones's "Photography of To-day," a volume which reviews pat and present photographic processes in a popular yet scientific way. On the very earliest history of the art, that is the work of Niepce, Daguerre, and Talbot reference may be made to a series of papers which ran through “The Photogram” for 1900. There are one or two issues of “The Photo-Miniature” which will usefully provide material, viz. those on "Who Discovered Photography”, “Colour Photography," and "Aerial Photography,” and as a means of faking a bird’s-eye view of the successive of photographic progress there is the monograph “Photography, Past and Present” issued as an illustrated supplement to the Diamond Jubilee Number of the “British Journal."
Focussing Sharply.
In focusing originals, such as paintings, in which the absence of definite outlines presents a difficulty, most photographers make use of a small printed card placed against the surface of the original in order to provide a workable test object. But perhaps it is not so generally recognized that different types of lens require different treatment in order to obtain the best results. As a rule, rapid rectilinears and other lenses possessing greater or less roundness of field give the best average sharpness when the test object is placed so that its image falls about midway between the margin and centre of the field. With most anastigmats it is best to obtain the greatest sharpness in the centre, and the margins will then frequently be sharper in the negative than they appeared on the screen. With all types of lenses great assistance can be given by a judicious use of the swing-back, both vertical and side movements being employed as needed. This is particularly the case when using a portrait lens at its full aperture; a swing of the back will allow of the same degree of good focus over the plate as could, be obtained by a smaller stop. The method must not be abused, particularly when a short-focus lens is being used, otherwise the size of hand and feet in the sitting figure will be unpleasantly exaggerated.
Patent Specifications.
A correspondent who addresses a query to us raises a point which no doubt is now and again in the minds of many other readers of these pages. It is a matter of common remark that the published specifications of alleged inventions to which patent protection is granted are often things which are as old as the hills or, on the other hand, bear on the face of them certain practical disabilities. But the explanation lies in the fact that the preliminaries in the way of search which are carried out before the granting of the patent extend, not to books and periodicals where the invention very likely has been published, but only to patent specifications themselves issued during the period of fifty years prior to the date of application. Moreover, the Patent Office is not concerned with the efficiency of an invention. It takes the applicant's word for its merits in this respect. Apart from its search in prior specifications its work is not very much more than a registration of the description of the invention and the claims made in respect to it. The questions of efficiency and of prior publication are left to be the subject of investigation in a court of law in the event of any action being taken as to infringement. While there are thousands of existent patents which have not been the subject of this legal inquiry, it is nevertheless true that a patent has not received absolute certification of value until it has been examined in the Courts. Inventors of photographic appliance: should not therefore set too high a value upon the fact that they may have teen granted a patent for a particular appliance. Nevertheless, it is a wise and not very expensive precaution to spend, say, the mutter of five pounds on obtaining protection for any invention before offering it for sale to a commercial firm. The patent rights can then be disposed of, and the co-t of maintaining the patent defrayed the purchasing firm if such is considered advisable.
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