This section is from the book "Complete Self-Instructing Library Of Practical Photography", by J. B. Schriever. Also available from Amazon: Complete Self-Instructing Library Of Practical Photography.
322. In our previous Instruction on Ordinary Developing we dealt principally with the use of necessary chemicals, and the manipulation of the different solutions in order to produce certain results. The formula for developing, given in this instruction, is intended for all classes of work, and should be universally employed for general portrait or commercial photography.
323. After numerous experiments with the formulae and instructions given in former lessons, you should have a fair understanding of the use of the different chemicals employed, and the advantage of altering the quantities of chemicals in the different solutions, from time to time, to suit the plate you are developing. Further, you should be advanced sufficiently to appreciate the advantage of the formula given in this instruction for rapid development of all classes of exposure,with little or no change of the developer, and yet produce the very best of results.
324. The simplest formula that one can employ, and yet obtain good results is always the surest and best. By applying the formula given in this instruction to all your future general work you will produce very uniform negatives, and with the slight altering from time to time to suit local water conditions every obstacle can be overcome.
325. You should profit, of course, by your previous experience with Ordinary Developing, and by applying the same method with the formula called for in this instruction superior results will be secured. This formula you will notice is divided into four solutions, the principal object of which is to have your normal developing agent (pyro) ripen in solution before using. If you were to prepare a gold bath for toning prints and use it immediately, without permitting it to set and become thoroughly mixed with the water, thus ripening the bath, it would work harsh and bleach the highlights in the prints; whereas, by allowing the gold and alkali to mix gradually with the water, and become thoroughly ripened, the bath works more evenly and smoothly, producing greater roundness, and a much more delicate effect. As it is with the toning bath so it is with the developing solutions.
326. If your developing agent is mixed from a concentrated stock solution directly with the accelerators of a less strength and then still diluted with water and immediately used for developing, the strongest chemical will attack the sensitized plate first. In this case the strongest chemical being your developing agent (pyro), the highlights are attacked, and if the plate is fully-timed the plate has lost its roundness before the accelerators have been sufficiently mixed with the pyro to supply the required softness. Thus, many times, plates that are really properly exposed, develop as though they were over-timed, and the same is true of under-exposures. The strongest chemical (pyro), attacks the highlights, and clogs the shadows before the alkali, or accelerator, has an opportunity to soften and open the pores of the film sufficiently to permit the developing agent to build them up, and assist in supplying detail.
327. This obstacle is overcome by permitting the developing agent (pyro), as well as the accelerator, to ripen before using. This you do by preparing your developer in four solutions and reducing the concentrated pyro stock solution to the strength required, ready for use, which proportions are equal to those of the sulphite and carbonate to supply a properly balanced developer. Each solution being prepared for some time in advance, all are well ripened, ready for immediate use, without adding water to the developer until just before using. If water is added at all it affects all the three chemicals alike, as all are diluted to their proper proportions, and are perfectly balanced.