REDUCERS 143 
IopIpDE AND Hypo (Lainer).—An extremely slow acting 
reducer, which is useful in the case of negatives generally 
fogged: 
Potassium iodide 10g 77 gr. 
Hypo 250 g 4 oz. 
Water 1000 ccm 16 oz. 
The negative should be immersed in this solution for from 
8 to 10 hours, or until the desired reduction is attained, then 
well washed. Prints may also be reduced in the same way. 
Ceric SULPHATE (Lumiére).— 
Sulphuric acid 4 ccm 30 min. 
Water 200 ccm 3 0z. 
Add: i 
Ceric sulphate 10g TE Sik: 
Stir until dissolved, then add: ; 
Water to 1000 ccm 16 oz. 
For use mix 1 part with 9 parts of water. This reduces the 
contrasts, and the negatives should be well soaked in water 
prior to immersion in the solution. For overexposed dense 
negatives, mix the above stock solution with an equal volume 
of water, and immerse the negative dry; care must be exer- 
cised, as the action is very rapid. There is no liability to stain, 
and the solution may be used still more dilute for prints. 
Iopo-CYANIDE.—Extremely poisonous, but clean acting: 
Iodine 6g 46 er. 
Potassium iodide 18g 138 gr. 
Water 30 ccm Y oz. 
Rub the iodine and the iodide together in a mortar or graduate 
with a glass rod, add the water, and stir until complete solu- 
tion is obtained; then add: 
Water 970 ccm 154 oz. 
Potassium cyanide lg 7.7 gr. 
