277. Fixing Bath

Fixing Bath. For fixing bath use plain hypo and water (4 ozs. hypo to 1 pt. of water), and during hot weather keep the bath cool. Allow plates to remain in this bath about 20 minutes, or about 10 minutes after all whiteness (bromide of silver) has disappeared. Should the plates show a tendency to frill in hot weather, prepare a hardening bath composed of 1/2 oz. of ground alum to 1 pt. of water, and immerse plates in same for two minutes, after fixing, and then transfer them to a washing box and wash for at least thirty minutes.

278. GENERAL NOTES.

Pyro. - Too much pyro clogs the whites. Too little pyro slows development; gives lack of brilliancy.

Alkali. - Too much alkali - Quick development; flat negatives; foggy and granular. Too little alkali - Slow development; contrast.

Sulphite. - Too much sulphite - Cold-gray tone. Too little sulphite - Warmer tone, inclined toward yellow.

Water. - Too much water - Thin high-lights; plenty of detail, but lack of snap and strength. Too little water - More contrast.

Temperature. - Normal, 65° to 70° Fahr. Higher temperature - Intensity and likely fog. Lower temperature - Flatness, lack of snap.

279. Drying Negatives

Drying Negatives. The warmer and closer the atmosphere in which the negative is dried, the more dense it becomes. Whenever possible, negatives should be dried with an electric fan, or in a current of air, as the quicker they dry (within limit - say within a few hours) the finer the grain will be.

280. Developing

Developing. All plates you believe to be properly exposed should be started in a normal developer. A correctly exposed plate can be completely developed with the formula for normal developer given in this instruction without any alteration whatsoever. It is advisable to always save the last developer used, pouring it into a large mouthed bottle and placing a cover over the bottle to protect it from dust. It is also well to use two trays when developing. Into one tray decant the clear solution of the old, or previously used, developer, adding one-third fresh stock solution thereto; use the other tray for normal developer.

281. Restraining Development

Restraining Development. If a plate flashes up quickly, indicating over-exposure, place it in the tray of old developer at once, rocking the tray quickly so that the bromide in the old developer, liberated from the emulsion of the plates previously developed, will penetrate the plate at once and check development. The bromide has a restraining action upon the shadows, but does not materially affect the action of the developing agent upon the high-lights, thereby permitting the developer to continue and produce the required contrast. Unless plates are very much overtimed, we advise using no other means of restraining than those described above. It is well after a plate has been developing in the old developer for some time, to place it in fresh developer, in order to give snap and more crispness, always being careful to rock the tray.