The members of the Photographic Society had a specially interesting meoting on the 30th ult, when the three Messrs. King, the Chinese students who recently returned from England, gave'a lecture on Platinotypes" and illustrated it by some of the fin ares over shown to the society. We reproduce some portion of the lecture. is to my idea the ming process we have for picture-making in photography. The simplicity-of working and the beautiful results will not fail to fascinate anyone who has used it. As to its pictorial qui although carbon is excellent, platinotyping has its own pee beauty, Plntinotype paper, as probably many of you know much better than I do, is a paper (any good drawing paper properly sized) sonsitised with a solution of chloroplatinite of potassium and ferric oxalate. The action of light reduces—forric into ferrous oxalate, and this when wotted with a suitable agent, in its turn reduces the platinum salt which gives the fine black image; useless to say this platinum image is as permanent as the support it is on. This paper could, of course, be made at home, but the London Platinotypo Company's produc tion being sv perfect, and sold at a fairly reasonable price, the amateur need not trouble to make it himself, especially as the "experiment is rarely successful, different kinds and sizes are made by the firm tamed and they lave sdlse placed on the market seusitised nainsook, and fifie und course linen, which ate, of course, much more expensive. Platinotypes can he made either in a fine black or " sepia; the working ix much the same with vithar, and ive will take the bick first. The paper is bought' in sealed tube, whic should be opened like a cigarette tin, the paper being taken out wholesale after the vuges of the tin have been smoothed with the back of a knife, If th paper is not all to be used wt once that remaining mast be kept in calcium tin, As a rule, however: careful the worker to preserve the paper from moisture, it be best to use up the whole of the paper within four.days, and by no means should any be kept mote than a woak.
Before printing it is necessary to find out the sort of negative best' suited for this kind of paper, mined by actual experience and crampies. Pure black negatives are thought the best by some workers but we oursd prefer a slight yellow tinge, i.e. negative developed with pyro-soda and the deve. loper not thoroughly washed out before fixing. Very yellow negatives, however, are apt to give grauular- prints. Negatives that will give excellent' prints-on P.O. less for plutinonot a brilliant.
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Text read from the printed page and cleaned; old type leaves the occasional error.