Every manufacturer of dry plates encloses in each box of plates packed for the market a formula for the development of the same.

The various manufacturers of dry plates, whose names will be found in the advertising pages in this book, each have a formula which in some respects differs from all the others, and it is but fair to the maker of the plate, that his formula should be used, unless the operator is of much experience and understands the requirements of each particular kind of plate.

Therefore, while formulae are given in this connection, although they are known to be of the best, yet in the hands of inexperience they may result to no better advantage than the formula appropriate to the plate used; consequently, we do not urge their use above any other, but rather that to which the operator is most accustomed.

The alkaline pyro developer is now in general use among professional photographers in this country, and there remains no doubt that it is the best developing agent for dry plates that has yet been brought into use.

This developer is composed of pyrogallic acid and an alkali, either ammonia, sal soda, or carbonate of potash, which, in solution and of proper strength, forms the medium through which the pyro is applied.

Camel's Hair Dusters.

To these is added bromide of potassium or ammonium, which is the restrainer, and occupies about the same position or performs the same function as acetic acid in the wet plate developer, and besides being a restrainer it greatly aids in securing intensity and printing quality; and when plates are overtimed in exposure its prompt use may result in securing a good negative.

Some plates require double the quantity of pyro that others do to produce the same quality of negative. After ascertaining the normal amount of pyro necessary to develop plates of a certain make, if it is desired to increase intensity add more pyro, if your plate is developing too intense or hard add more of the alkali.

Dry Plate Developer, A

No. 1.

Carbonate of Soda (Sal)................ 1 lb.

Carbonate of Potash..................... 1 lb.

Yellow Prussiate of Potash.............. 1 oz.

Bromide of Ammonium................ 1 oz.

Water.................................64 oz.

No. 2.

Pyrogallic Acid........................ 1 oz.

Saturated Solution Sulphite Soda..........15 oz.

Keep No. 2 in glass-stoppered bottle. To develop one 8x10 plate, take of

No. 1................. ............. 1 dr.

No. 2................................ ½ dr.

Water............................... 6 oz.

Put the exposed plate into the developing tray and pour the solution upon it, making sure that all parts of the plate are covered, and no air bubbles fixed to the surface; keep the dish in motion and in a short time the image will begin to appear; if properly timed the high lights will show up promptly, and in due time all parts will appear, and when detail is seen in the shadows take the plate from the dish and examine it by transmitted light. Note the gradations of light and shade; if they appear properly balanced, the plate has been properly timed in exposure. Return the plate to the dish and let the development proceed until the image sinks well into the film and you see nothing very clearly as it lies but the blacks.

Time is necessary in this process to secure enough intensity, and this stage is the most difficult in the process, there being no means by which to judge with any degree of certainty the density of the image before you. It is better then to proceed too far than not far enough, as a slow printing negative is far better than one that is too thin and weak.*

When the image has sunk pretty well into the film examine it again by looking through it, and note well its appearance, so that if it is about right when fixed you may remember how it appeared if you wish to increase or diminish the intensity of your next plate.

If the plate has been overtimed it will show up quickly, almost at once; when such is the case quickly pour off the developer and flow the plate with water, washing it well, then prepare more developer with nearly double the amount of pyro and a few drops of a strong solution of bromide of ammonium, which, add to the 6 oz. of water and pour on the plate; then take half the usual quantity of the No. 1 solution in a graduate and pour it, a few drops at a time, into the developing tray, watching the action closely and keeping the solution in motion.

* These directions apply to all dry plates except the Stanley, which can be developed to any required density at sight, and loses none in the fixing solution.

The negative at this time probably shows all the detail of the subject, but without any gradation of intensity. If the changes just described have been made promptly you will soon observe that the high lights will begin to gain in strength. Keep up the action by adding more of the alkali, drop by drop, until you can proceed no farther.

The chances are that you will secure a printable negative, but not a very good one; and if it is a portrait the best thing to do is to throw it away and make a new one.

The plate should now be very carefully washed previous to fixing.

Should the film show signs of loosening from the edges of the glass and swell so as to form folds or frills, take it from the water and immerse it in a solution of alum, which will harden the film and stop the frilling. Then wash the film again and put it in the Fixing Solution

Fixing Solution

Hyposulphite of Soda.................. 1 lb.

Alum................................ ¼ lb.

Water............................... 1 gal

When the soda and alum are dissolved let it stand until all sediment settles to the bottom, then pour off the clear solution and use it to fix until from much use it becomes black and turbid, then make up and use a fresh solution.

The plate should be left in the fixing solution for fully five minutes after it appears thoroughly cleared, then take it out and wash until all traces of hypo are removed.

If the plate has not previously been in the alum solution it may now be put in the Clearing Solution

Clearing Solution

Alum............................... ½b.

Citric Acid......................... 2 oz.

Water.............................. ½ gal.

Keep this solution in a flat dish, and after the plate has been washed from the hypo put it in this solution for two or three minutes; if there are any remaining traces of hypo in the film it will be decomposed, the film will be hardened and freed from color; when this is accomplished wash again and set the plate up to dry.

While the alkaline pyro developer is the best and gives the finest printing quality to negatives, there are many who prefer (for other reasons) the Ferrous Oxalate Developer.