Kodak paper dating guide
These notches are used by photographers to determine the emulsion side in the dark. Film pack negatives were produced in the same sizes as sheet film. Many families may have a small number of these negatives stored in their home with no idea of the hazard they represent. Professional 35mm motion picture film is the most hazardous type.
Film packs used a much thinner and a very flexible based film. They lack a notch code, but may have a negative number, generally 1 through 12. All nitrate 35mm motion picture film should be duplicated by an authorized laboratory.
Large quantities of nitrate film have caused several disastrous fires.
Due to the inherent instability of cellulose nitrate, much of our photographic legacy from this period is disappearing.
Therefore, just because you see the word “nitrate” does not guarantee that it is. If a negative can be accurately dated, either by subject or by the photographer's notes, it is possible to determine if it is nitrate film. It has always been a common practice for photographers to purchase bulk rolls of 35mm motion picture film and re-spool it into cassettes for still camera use.Deteriorated nitrate negatives are easy to identify, but nitrate negatives in good condition are almost visually indistinguishable from other types of transparent films. The words generally identified the manufacturer and the type of film: nitrate or safety.Unfortunately, not all manufacturers adopted edge printing identification.It wasn’t done on either early nitrate negatives or onsome roll film formats.Amateur roll films were not marked but can be identified by their tendency to curl very tight scrolls (later roll films were coated on both sides to prevent such curling).