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June 22, 1883.] THE PHOTOGRAPHIC NEWS. 391 as yet known to the_.time during which plates will keep if Plates may be packed in opaque orange paper, such as is sold by most photographic dealers. The paper usel for the mikin b Sulphite of soda (crystals) Bromide of ammonium... Bromide of potassium ... Pyrogallic acid ... ... stored in perfectly dry pure air. They are very readily des troyed, however, by damp, gas fumes, &c. ALKALINE PYRO. DEVELOPER ALL IN ONE SOLU- T10N. BY G. CRAMER. Having perused with much interest the articles appearing in the photographic journals on the preserving influence of sulphite of soda over pyrogallic acid, I will say that my experiments with it have been so successful that I do not hesitate to pro nounce it the most reliable and finest developer that can be used for dry plates. I have combined all the chemicals in one solu tion, which keeps well, and only needs diluting with water to be ready for use. The diluted solution can be used repeatedly. It is simple, economical, and durable, and the resulting negatives are extremely fine in colour and printing quality. My formula is as follows :— Stock Solution. 3 ounces troy weight } ounce „ ,, 12 ounces „ » 2 n „ » Dissolve thoroughly in pure rain, distilled, or ice water 32 fluid ounces Add sulphuric acid (c. p.) (120 minims) Finally strongest aqua ammonia 3 fluid ounces Add water to make up bulk to... 40 ounces Be careful to measure the sulphuric acid and the aqua ammonia very exactly, and keep the latter in a cool place, well stoppered, so that it will retain its full strength. (Instead of three ounces of crystals, two ounces of granular sulphite of soda may be substituted to produce the same effect). The solution assumes a bright ruby colour, and will keep a long time if kept in a bottle with tight-fitting india-rubber stopper. Dilute sufficient for one day’s use as follows:— For ordinary purposes, 1 part to 11 parts of water. For very short exposures, use 1 part with 3 or 6 parts of water. For over-exposed plates, or in all cases where great intensity and contrast is desirable, 1 part to 20 of water. In developing a plate which was over-exposed, the shadows will appear too soon. In this case add as quickly as possible more water to retard the development, and to produce more intensity. If the shadows appear too slowly (from under-exposure), add more stock solution, as the stronger developer will produce more detail in the shadows, and less intensity in the lights. The additional stock solution should be poured in the corner of the developing dish, as it would cause stains if applied directly to the plate. Always develop until the shadows have sufficient detail. Wash well before fixing, and prepare the fixing bath as follows:—First dissolve a half-pound of powdered alum in one- third of a gallon of water ; then dissolve one pound of hypo in two-thirds of a gallon of water. After both are dissolved, pour the alum solution in the hypo. The alkaline pyro and sulphite of soda developer can be used repeatedly as long as it remains clear, if the solution is always returned to the pouring-bottle, which should be provided with a tight-fitting india-rubber stopper, to prevent evaporation. If the mixed developer has been standing a while, shake before using, and wait a few seconds until the air-bubbles havedise appeared. As long as the solution remains transparent, it is all ’ right; but when it looks muddy, its use should be discontinued. of “ masks and discs ” is the best. The plates may be packed in sets of four or six. Every two plates are put face to face, and have a piece of tissue paper between them. Three packets of 4, or two of 6, are then taken, and wrapped together in a thickness of opaque orange paper. Two wrappings of brown paper are then put around all, and the package may be handled in any light. For amateurs, who never make a very large stock of plates, the best course is to use grooved light-tight boxes. Such made of wood are very expensive, but paste-board boxes, which are very handy, are made by Mr. B. J. Edwards, of 6 and 9, The Grove, Hackney, London, for storing his own plates in. We do not know whether or not Mr. Edwards supplies the market with the doxes, but he is generally willing to oblige amateurs with a few. The grooves of these boxes are made with paper, and some little practice is necessary before the plates can be slipped in with out tearing this. If a little patience be exerted at first, however, all will go well.