Alcohol and ether, equal parts.
Anthony's Negative Cotton 3 grains to ounce
Anthony's Climax Cotton 1 " " "
Put the cotton into the ether and let it become saturated, then add
the alcohol. Excite with [p027]
Iodide of Ammonium 3-1/2 grains to ounce
Iodide of Cadmium 2 " " "
Bromide Cadmium 2-1/2 " " "
Collodion sometimes, from long keeping, loses sensitiveness and
becomes of a deep red color. When such is the case, it should be set
aside and fresh samples prepared, which would be improved in working
quality by the addition of small quantities of the old, and thus old
stock may be used up without deterioration in the work.
Negative collodion should not be so heavy bodied or thick as that
for positives; neither should it be so highly excited. Good positive
collodion should have as many as 8 grains of the iodides and
bromides to the ounce, requiring a silver solution not lower than 50
grains strong and going somewhat higher in cold weather.
The standard silver solution for negatives is 45 grains of silver
nitrate to the ounce of water and the collodion from 5-1/2 to 6-1/2
grains to the ounce, with a tendency to less in cold weather.
Collodion for negatives should be permitted to ripen a day or two
before using, unless it is brought to that state by mixing with old.