970. Silver Bath

Silver Bath.

Silver Nitrate .............

....................8 ozs.

Water (Distilled) ...........

.................120 ozs.

Iodide of Potassium .......

...................10 grs.

Nitric Acid (C. P.) about 15 drops, or enough to turn litmus paper slowly red. Then the bath should be carefully filtered. This should test 42° with the hydrometer.

971. Before making an exposure of a plate, other necessary solutions should be made up ready for use, as follows:

972. Developer

Developer.

1 oz. Protosulphate of Iron dissolved in 20 ozs. of water.

Acetic Acid ................

...................4 ozs.

This should test 20° with the hydrometer.

973. Fixing Solution

Fixing Solution.

Potassium Cyanide

1 oz.

Water

18 ozs.

974. No. 1 Intensifier.-

4 ozs.

Sulphate of Copper in 20 ozs. of water.

2 ozs.

Bromide of Potassium in 20 ozs. of water.

Then mix together.

975- To "blacken" negatives made with this inten-sifier, use a solution of 1/2 ounce of silver mixed with 6 ounces of water.

976. No. 2 Intensifier.-

977. To "blacken" negatives made with this intensifier, use a solution of 1/2 pound sulphate of soda mixed with 32 ounces of water.

978. Reducer

Reducer.

Potassium Cyanide

.............60 grs.

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

..............6 ozs.

Iodine Solution (made as follows)

...........10 drops.

979. Iodine Solution

Iodine Solution.

Iodide of Potassium

1 1/4 ozs.

Iodine (Resublimed).........

1/2 oz.

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

16 ozs.

980. With the different solutions all prepared ready for use, the next stage in the operation is to coat the plate with the collodion solution, then immerse it in the silver bath, slowly lowering, without stopping for an instant, until it touches the bottom (otherwise it is apt to show streaky). The plate should then be left in the silver bath for three or four minutes. While this is being done the operator usually is tacking up his copy and adjusting the focus on his camera. To get the picture sharp on the ground-glass use the lens wide open; then, placing the cap

Bichloride of Mercury

1 1/2 ozs.

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

..............20 ozs.

Ammonium Chloride

1 oz.

on the lens and inserting a small diaphragm, and after removing the ground-glass, the camera will be ready so the plate-holder may be placed in position.