THE DEVELOPMENT OF THE PLATE carefully followed the instructions for developing given in the preceding chapter, and arrived at the result therein recorded, we proceed to take the second plate in hand, to which, it will be remembered, we gave an exposure of four seconds.
To do so, we begin by making up a developer of the same strength as before, and which stood as follows : Pyro. solu tion, CO minims ; bromide solution, 40 minims ; ammonia solution, 30 minims; water, 3 oz. This we have called our " normal developer," and if the exposure has been approxi mately accurate, it should be sufficiently strong, with very little further addition of ammonia, to bring up a good negative. The beginner should make it a rule, at any rate until he has gained some experience, to commence development with a solution of a certain strength, and he cannot do better, for general purposes, than adopt the formula which has just been given. By working in such ft manner it will be more easy for him to determine whether the plate has been correctly exposed, and according to its behaviour under the normal developer he will be able readily to determine whether it be either correctly, under, or over-exposed.
Having mixed the developer, the routine laid down and described in the last chapter must be again carefully followed. Wo will assume, therefore, that the plate is in its dish, and that the developing solution has just been poured over it. We must now carefully watch it, and contrast mentally what takes place with what occurred when we developed the first plate.
If all the instructions have been observed, we shall that in about a minute that portion of the plate which represents the sky, and which, of course, has received the greatest amount of light, will to darken, and then, in proper sequence, the rest of the picture will slowly and regularly appear, and, as the action proceeds, the image will gain in strength and detail till, after the lapse of about five minutes, the whole of the picture will appear to have deve loped. At this stage the plate should be removed from the developer, and, after a slight wash, may be held up to the orange light for a hasty scrutiny. This will probably reveal the fact that although plenty of detail is apparent in the negative, it yet lacks the necessary density. We, therefore, measure into the developing cup another ten minims of ammonia solution, together with ten of the bromide solution, and again pour the slightly strengthened developer over the plate; the effect of this addition will be to slightly increase the energy of the developer, and in about five minutes we may remove the plate from the solution, wash off the developer, transfer to the alum bath, again wash, and then fix. We have this time succeeded in producing what should
bo technically a perfect negative.
We will not, however, rest here, but in order to learn as much as we can on this all-important subject of develop ment, we will proceed to develop the remaining plate, to which, it will be remembered, we gave an exposure of six coeds. If we reflect for a moment upon the behaviour of the tkvo plates which we have already developed, we shall at once, and rightly, assume that this last plate has been over-exposed. Now there are several methods, when we know that we have over-exposed our plates, by which we can to some extent counteract its effect, and these we shall consider when we have gained a little more experience ; but for the present we will adopt the mode of working which has already been advised. We, therefore, mix up for the third time our " normal developer," and apply it to the plate. We must, however, watch its action very closely, for almost as soon as the surface of the plate has become thoroughly wetted with the developer, the image will begin to appear. With the weak solution with which we are working this may at once be accepted as evidence of considerable over exposure, and prompt measures to counteract the effect of this must be taken. The developer is immediately poured away (for it will be necessary now to mix a fresh one of different strength), and the plate well washed under the tap. A fresh developer is then to be compounded as follows : Pyro., 80 minims; ammonia solution, 20 minims ; bromide solution, 80 minims; water, 3 oz. This modified solution is then applied to the plate, which, under its influ ence, if the amount of over-exposure has not been very excessive, will slowly acquire density. If we refer back to the chapter dealing with the preparation of the various solutions, we shall find the properties of the different con stituents of the developer briefly described, and if we follow this out a little further we shall be the better able to under stand the reasons for thus modifying the development, and its consequent effect upon the plate.