107. Tank Development

Tank Development. Another very good way is to use tank development. This method requires a larger quantity of solution, but several plates may be developed in this tank at one time. Provide a deep galvanized iron, or better still, a deep rubber grooved box, a regular hypo fixing box - a new one of course - one that has not been used for any other purpose. Fill this tank half full with developer, then add water to within one inch of the top, and stir well. Then place the plate, or plates, in this tank, covering it to exclude all light, and allow plates to remain half-hour, when they should be completely developed. If, upon examination, they are not strong enough, allow them to remain in the tank until fully developed. Owing to the large bulk of solution the tank developer will last for hours without renewing. See Chapter XIX (Gum-Bichromate Process), Tank or Stand Development.

108. Action Of The Pyro

Action Of The Pyro. The very small quantity of pyro used in developing under-exposed plates gives the accelerator an even opportunity to thoroughly open the pores of the film. The highlights having been fully timed, or possibly a trifle over-exposed, will naturally develop soft on account of the small quantity of pyro used. If the regular amount of pyro had been used in long development, these highlights would clog and become very dense. Having, however, used only a small quantity of pyro, this will allow for extremely slow development. Consequently, the plate, instead of developing hard and contrasty, will be clear in the shadows, soft in the highlights, and full of half-tones.

109. Developing Of Doubtful Exposures Which Prove To Be Considerably Under - Exposed

Developing Of Doubtful Exposures Which Prove To Be Considerably Under - Exposed. Such plates should be started in normal developer, and as soon as the highlights appear, if you observe the shadows are holding back, with practically no detail, and the highlights are building up slowly but very strong, it is a certain indication that the plate is under - timed; so at once place the plate in a tray of plain water. Owing to the fact that the plates are partially developed they cannot be placed in the accelerator bath, as given in paragraph 105, for the accelerator alone after the developing agent has once been applied would be liable to cause a chemical fog - therefore the safest treatment is a plain water bath. Allow the plate to remain in the water for ten or fifteen minutes, covering the tray so as to exclude all light and air. While the plate is in the water prepare a new developer, weak in pyro. Take two drams of your pyro stock solution, add one ounce of sulphite of soda solution (hydrometer test 70), and one ounce of carbonate of soda solution (hydrometer test 40), and then add sixteen ounces of water. Remove the plate from the water, and complete the development in this bath.

no. If the shadows fail to come up and still lack detail, it is well to gently press the ball of the hand, or the tips of the fingers, on the portions that will not develop, permitting the heat from the hand to warm that part of the plate, thereby assisting in developing more rapidly. Breathing on these parts of the plate will also have the same effect.

III. Developing Normal or Slightly Under-Timed Plates. - Place your plate in normal developer. Just as soon as the highlights begin to appear, carefully examine the plate by holding it before the ruby lamp, and if you find that the shadows are developing slowly, with little or no detail showing in them, the highlights building up contrasty but slowly, you will at once know that the plate is a trifle underexposed. Transfer it to a tray of fresh water, and allow it to remain for ten or fifteen minutes. You will be surprised to see how much detail the plate will develop in plain water after it has been transferred from a developer, in which it has been developing for a short time. Allow the plate to remain in the plain water for a few minutes, and when you find that sufficient detail has been produced in the shadows, return it to the normal developer. If the plate was over-exposed instead of under-exposed, and should you leave it in the plain water too long, you would produce a flat negative, often times producing fog in the shadows. It is, therefore, necessary to closely watch the plate at all stages, whether in the water or developer, and be certain the plate is either under or over-exposed before you attempt to alter the developer.

112. We would advise in ordinary developing of white drapery, where there is red or black hair to contend with, that you remove the plate from the developer as soon as the image appears, and hold the plate under the tap, permitting the water to fall on the hair, or portions you desire to develop more quickly. A few moments of such treatment helps the general result considerably.

113. To produce softness in the white drapery itself, place the plate under the tap just as soon as the image first appears, allowing the water to fall on the portions which do not develop freely. This will many times improve the negative.

114. Of course a great deal depends upon the temperature of the water you are using, also the temperature of the developer. When developing under-exposures the water should never be colder than 65° to 700 Fahrenheit. In winter months the chill should be taken off the water for all exposures, whether under-timed or fully timed, and should be kept at about the same temperature as in the summer months. In cases of developing under-exposures, it is advisable to have the developer never below seventy in winter, and sixty-five in summer. Do not attempt to develop under-exposures in cold, dark rooms. Try to have the temperature of the dark room at least sixty degrees. If the dark room is cold the developer soon becomes chilled, and the action is much slower and will retard the development of the deepest shadows.

115. In case of warm climates or extremely warm weather, when the developer being warm is liable to cause the film to soften and perhaps frill, it is advisable to use an acid hardening hypo bath, prepared as follows:

116. Acid Fixing Bath : -

(A)

Water..............................

100 ounces

Hypo...............................

2 pounds

Sulphite Soda (granular)............

2 ounces

(B)

Water...............................

32 ounces

Chrome Alum ......................

2 ounces

Sulphuric Acid - C. P...............

2 drams

If by Hydrometer test

(A)

Hypo test 8o°............

100 ounces

Sulphite Soda Sol. test 6o°

16 ounces

If by Hydrometer test

(B)

Chrome Alum test 200 ....

32 ounces

Sulphuric Acid C. P......

2 drams

117. After the ingredients are thoroughly dissolved, pour B into A slowly, while stirring A rapidly. This bath remains clear and fixes clean, after long continued use, but should be replaced as soon as the fixing becomes slow, as the bath is then exhausted. Allow the negatives to remain in the fixing bath at least five minutes after the whiteness has disappeared. The longer the plates remain in the fixing bath the less washing will be required, and with the acid bath the film also becomes harder, and fifteen to twenty minutes washing is sufficient.

118. A smaller portion of the bath can be made up if one so desires, but as the larger bulk keeps better, and if one has considerable developing to do, it is better to make up the full amount. If only an occasional plate is to be developed each day, then one-fourth the formula is sufficient, or one may purchase the regular acid hypo put up in small packages, making sixteen and twenty-four ounce solutions. These stock acid hypo solutions can be obtained from any supply house.