This section is from the "Studio light a magazine of information for the profession 1918" book, by Sara F. T. Price. Also see Amazon: Studio light a magazine of information for the profession 1918.
In certain localities trouble in drying negatives evenly is experienced in cold damp weather, and even in the warmest weather when there is considerable humidity.
This trouble is often due to placing the negatives too close together in the drying racks, the result being a sharply defined edge to the portions which have not dried.
When negatives are left to dry over night and the studio is opened the next morning and the work rooms ventilated, the weather may have changed, the air cleared up and the portions of the negatives that remain damp dry very quickly with a marked difference in density and the drying mark mentioned above.
No after treatment has ever been found that would remove such a mark. If negatives have dried slowly in a closed room, close together in the racks, the only way to save them is to keep the room closed and allow them to finish drying under those conditions.
The best way to prevent drying marks is to dry the negatives quickly. All of the surplus moisture should be wiped from the front and back of the negative with a damp pad of cotton.
Negatives should be placed a couple of inches apart in the racks and once they have started to dry in one room should not be carried into another. Or if drying has begun in a well ventilated room the room should not be closed later on and the rate of drying changed.
If the air is damp it is advisable to heat the drying room before the negatives are placed in it for drying. There will then be little chance of their not being dry by next morning.
Every studio should be equipped with an electric fan for quick even drying, the results being most satisfactory in every way. The time saved in drying negatives ready for proofing enables one to show proofs before the sitter's enthusiasm begins to wane, and orders are almost invariably larger.
Thin negatives are considerably intensified by quick drying and the combination of a fan and heat may be used to advantage in drying such negatives. Precaution should be taken to see that an inexperienced apprentice does not turn the negatives upside down in the racks once they have begun to dry.Watch the work of the man who uses