Most manufacturers numbered their stocks following some kind of pattern or method. As a result, at a quick glance, these numbers can sometimes immediately tell you what the purpose or composition of the stock is, although companies haven’t always stuck to these internal rules throughout their history. This page will attempt to gather known information about stock numbering/naming for various film stock companies.
ANSCO
Although there are exceptions I’m still researching, 16mm Ansco stocks generally begin with a “2” and 35mm stocks with a “7”, although there are also a batch of Ansco stocks beginning with “8” which may also be 35mm.
EASTMAN KODAK
Kodak stocks are generally identified by a four-digit number, such as 7252 or 5249. Most commonly, the first digit of this number will tell you the gauge and base composition of the stock:
1st digit “2” = 35mm polyester
1st digit “3” = 16mm polyester
1st digit “5” = 35mm acetate
1st digit “7” = 16mm acetate
Although the above convention is followed in most cases starting in the 1960s, there are sometimes deviations pre-‘60s, such as 5xxx stocks being used for 16mm, among other examples.
“SO-” before a stock number means “Special Order”, which indicates a stock that is not a regularly available catalog item but something requiring a special order to fill. Sometimes, newly introduced stocks are given an “SO-” number in their trial phase, before being given a proper four-digit number once added officially to the catalog. Polyester versions of acetate stocks were sometimes historically given an “SO-” stock number, such as LPP print stock 7384, which in its polyester version was SO-396.
LIGHTSTRUCK 