Never exceed one ounce of No. 2 (iron) to three ounces of No. 1 (potash), for if you do you will form a sandy deposit and discontinue the action of the developer.

Always develop until the picture seems sunken into the surface. Do not judge by looking through the negative only. Wash and fix in hypo, 1 ounce; water, 8 to 10 ounces. After fixing, wash well.

For pictures taken instantaneously, use no bromide in the developer.

COOPER'S SODA DEVELOPER.

"No. 1.

Anthony's Sodium Sulphite Crystals¾ lb.
Distilled water 2 qts.
Anthony's Pyrogallic Acid2 ozs.

No. 2.

Anthony's Sal Soda Crystals½ lb.
Water2 qts.

To develop, take

No. 12 ozs.
No. 22
Water2