TANK DEVELOPMENT.

By C. H. CLAUDY.

HE old order changeth and maketh way for the new." When the dry plate came, the exponents of the old order howled. Yet to-day the wet plate is nowhere, except in engraving plants and laboratories where all the photography is done within ten feet from the dark room.

When the film arrived people decried it still do, for that matter, yet barring its expense, it is pretty generally recognized that film is on a par with plates as far as results are concerned.

It has taken, lo, these many years for the truth about development to get even a foot hold in the minds of photographers, both amateur, and professional alike; yet there is no question as to the facts,-time and temperature and original make up of solution are the deciding factors, after exposure, in the kind of negative-and all the addition and subtraction and change and jugglery in the world won't help a plate which has once started to develop.

The facts have been proved. When a fact is proved to be a fact it ceases to be a matter of controversy-the only room for argument is whether or not it has been proved. To prove an established proof is sometimes troublesome, but not in the case of the tank, since the expenditure of a small sum of money and an honest following of instructions will prove it anew to any one who wishes to make the trial.

As the fact has been proved to me, and as I have proved it several times for myself, I am not going to argue about it with you who read. But I am going to set down a very simple and easy way for you to prove once and for all for yourself whether or not time and temperature development is good or not.

Now all rules for tank development, meaning rules as to constitution of solution, temperature and time, vary with the particular brand of sensitive material employed. So the instructions for one plate will give very poor results with another. Half the time people try the wrong formula on a plate and then blame the theory instead of their own mistake. So you will please use a roll of Eastman film in making this test and follow exactly the maker's instructions as to the developer.

Take of pure, anhydrous sulphite of soda, 90 grains. Take of pure, anhydrous carbonate of soda, 60 grains. Dissolve these thoroughly in three pints of water and see that the water is at the temperature of 65 deg. Fahr. This means sixty five degrees, and not sixty or seventy. Just previous to development stir in the solution 30 grains of pyro.

Now, you should have two rolls of film, with exposures varying as widely as you please from snap shots to time exposures, but all as nearly as possible the correct exposure for the subjects they have reproduced. One of these rolls of film you are to develop in the solution given above for exactly twenty minutes, in the regular film tank, according to instructions.

The other you are to develop your way, whatever that may be -in the roll, in the piece after cutting them apart, juggling, arranging solutions, any way you think you know which will improve the resulting prints. Unless your way is to develop in the strip, and for a sufficient time to give the most over exposed negative its normal contrast, the tank negatives will be better than the ones you make by hand. How can I say that? Because I have tried it and seen it tried time and again. The tank makes the better negatives, the cleaner negatives, the crisper negatives. No, it has nothing to do with films or film tanks. Any plate tank and any plates will do the same, providing you have the right formula for that plate and the right strength of solution at the right temperature, and leave them in the right time. The formula is published for Eastman Film,—I do not know that it is published for any plate. Hence I took the film as an example, not wanting to offer the results of my own experiments as established facts, regarding the plates I use..

Now carry this test further. Make a lot of under exposures on a roll of film-make a duplicate for your own hand work. Expose a roll of film and have them all over exposed. Do the same for your own roll. Develop two in the tank and two by hand, but don't start those by hand in a restrained solution, for you must be fair and you will admit that you do not usually know when you start development that a plate or film is over exposed. If you did know, you wouldn't have so exposed it. After the development has started pile in bromide all you please. And again, I am positive that the tank results will give better prints than those you have developed by hand-at the outside, they will give prints fully as good, which shows the method has done all you have done and with infinitely less trouble. In fact there is no test you can put a tank to-no manner of exposures, and no contrast between exposures, which the tank will not do as well with and nine times out of ten better than you or any one else can do by hand. And the reason is in no magic or no change from old things to new, but simply that the scale of tones is determined by the exposure-the steepness of the scale by the time and temperature of the developer. You can't alter the exposure once it is made-you can't alter the scale once it is made. You can alter the steepness of the

scale (contrast) by the time of development and you can alter it by altering the constituents of the developer before the scale starts to develop,-beyond that, development has no control in the making of the negative.

Exception of course, is made of local development and such methods as wilfully fogging, or flattening, for pictorial effect. These are beside the question and have no bearing upon it.

It is because the tank operates upon established lines, and because it is based upon scientific facts, that its worth is indisputable, the only thing you can dispute is whether or not this has been proved, and the test lies in your own hands.

Go and do likewise, and join the gradually increasing army which believes in making the negative in the camera, and leaving development to the laws of nature which govern it.