Wednesday, June 25, 2008

EX CATHEDRA: Complete Development; Colour of Second-hand Lenses; Camouflaging the Camera; Varnishing Negatives.

Complete Development

            The maxim which is rightly emphasized to makers of bromide prints, namely, to develop thoroughly, is one which even now, although it has been repeated over and over again, is largely disregarded. Neglect of it is one of the chief causes of unsatisfactory quality in sepia-toned prints, the results of toning an image which has been rapidly and, therefore, superficially developed being greatly inferior to those in which development has been carried more deeply into the film. One rule which has been given for the guidance of bromide printers is that the time of development should be at leant three minutes, and exposure adjusted accordingly in order that the print at the end of this period of development should not exhibit the effects of over-exposure. But papers and developers having their particular idiosyncrasies, perhaps a more usefully applied rule for discovering whether prints are receiving this "full" development is to immerse half of s print only in the developer, and after the expiration of, say, half a minute to allow the developer to act upon the whole. If, then, development can be continued so as to yield a satisfactory print which does not show a difference between the two halves, the worker may be satisfied that his development u of the required fullness. On the other hand, a difference between the two halves will indicate that exposure can be advantageously cut down.

Colour of Second-hand Lenses.

            Those who are baying secondhand lenses will do well to give the question of colour some consideration. As is well known, long exposure to damp or atmospheric conditions lead to discolor the glass of the lens, or cause the balsam cementing the components to deteriorate with the same result. Some secondhand lenses that we have seen suffer from this very badly, the glass having quite a yellow tinge, in others, though existent, the defect is not so apparent, but if present the marked aperture of the instrument does not represent its actual working speed. We had one inch lens that when examined in a casual way showed little or nothing the matter, but when placed against a sheet of pure white writing paper a slight discoloration was at once noticed Slight though this was, it had a marked slowing action when using ordinary plates, though when orthochromatic emulsions were employed this to a large extent disappeared. Those having such instruments will do well to send them to one of the firms advertising in the advertisement columns of this Journal for repolishing or recementing of the glasses as the case may be, while if buying a secondhand instrument prospective buyers should be on the watch for a defect, which, though it might easily peas unnoticed, reduces the actual value of a lens very considerably. This discoloration is perhaps more frequently met with in the older instruments than in the modern anastigmats, unless these have been very much exposed to bad conditions, but it is a condition of things that all owners of good cemented anastigmats will do well to guard against.

Camouflaging the Camera.

            We commented recently upon the use of the small camera in certain branches of photographic work where its advantages may be turned to good account. A further instance of its value as a supplementary instrument in the studio was told to us the other day by a professional friend. He was commissioned to make a portrait of a child of whom previous experience had taught him that, however pleasing might be the expression on the little sitter's face, it instinctively froze directly the operator made a move towards the camera. The studio instrument was prepared in the usual way, and in front of it was placed a table with piles of books, etc., very carefully arranged to conceal a previously focussed vest-pocket camera, with its shutter set ready for an exposure. The usual attempts were made with the studio instrument and with small hope of obtaining a satisfactory picture. The operator turned away rather disgusted. Almost at once the little sitter was herself again, and casually, as it were, turning to the table the operator pressed down the shutter release of the vest-pocket camera, covering the action as if by taking up a book. As was expected, the exposures made with the studio camera were failures from the point of view of expression, but the small camera yielded a lifelike and pleasing portrait. The negative was carefully enlarged, and the result was an order for some dozens of prints. The idea of camouflaging a small camera should prove of value to those photographers who have to take portraits of nervy sitters, since the exposure may be made at a selected opportunity without the sitter being aware of it. Such a plan should help in overcoming many a difficulty in this respect. Though the negative is small, the quality can be of the best, and the resulting enlargements with a little working-up should give no indication whatever that they are not contact prints from large-sized original negatives.

Varnishing Negatives.

            Few photographers at the present time varnish their negatives, nor when ordinary bromide printing or enlarging is to be the medium is this course really necessary. But when a number of P.O.P. carbon or platinum prints are required from one negative, and the printing is done in the semi-open air for the most part, in damp weather it is a wise precaution to give the negatives a coat of ordinary cold varnish. Many present-day operators, however, find a great difficulty in getting an even coat of varnish over the entire plate by the ordinary method, and if this is not done there is a tendency for the varnish to dry in ridges, which means, of course, corresponding markings on the prints. Varnishing negatives by flowing the varnish on and tilting the plate at various angles until the whole is covered, and then draining the surplus back into the bottle, is an operation that requires a certain amount of skill, which can only be obtained with practice. We have for some time past varnished our negatives with an ordinary camel-hair (or hog-hair) brush. The exact kind is not very important, provided that it is well made and free from loose hairs. For this method, though not strictly orthodox, we may claim that it is comparatively easy to put a light but even coat of varnish on the film. None of the varnish need be got upon the back of the plate, and negatives may be very rapidly treated. Care should be taken not to get the brush too full of the varnish, or uneven coating may result. To those who have had no experience of varnishing negatives this alternative method may be recommended, although the essential feature of it is that a thin coating is rapidly applied.

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