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Cellulose diacetate film was first created by the German chemists Arthur Eichengrün and Theodore Becker, who patented it under the name Cellit, from a process they devised in 1901 for the direct acetylation of cellulose at a low temperature to prevent its degradation, which permitted the degree of acetylation to be controlled, thereby avoiding total conversion to its triacetate.
Cellulose acetate is also known as "safety" film and started to replace nitrate film in still photography in the 1920s. [1] There are several types of acetate that were produced after 1925, which include diacetate (c. 1923 – c. 1955), acetate propionate (1927 – c. 1949), acetate butyrate (1936–present), and triacetate (c. 1950 – present). [1]
It can happen during a film screening when a frame becomes stuck in the projector's film gate. Acetate films are also subject to degradation over time. With exposure to heat, moisture, or acids, the acetyl groups are broken from their molecular bonds to the cellulose. The now free acetic acid is released into the air. Acetic acid is vinegar ...
Cellulose acetate film, which was the initial replacement for nitrate, has been found to suffer from "vinegar syndrome". [14] Polyester film base, which replaced acetate, also suffers from fading colors. [5] Storage at carefully controlled low temperatures and low humidity can inhibit both color fading and the onset of vinegar syndrome.
Cellulose acetate film, made from cellulose diacetate and later cellulose triacetate, was introduced in 1934 as a replacement for the cellulose nitrate film stock that had previously been standard. When exposed to heat or moisture, acids in the film base begin to deteriorate to an unusable state, releasing acetic acid with a characteristic ...
Nitrate film was replaced with acetate-base films. These Cellulose acetate films were later discovered to outgass acids (also referred to as vinegar syndrome). Acetate films were replaced in the early 1980s by polyester film base materials which have been determined to be more stable than film stocks with a nitrate or acetate base.
How stable the film is depends largely on the type of stock, but film, if well taken care of, is generally able to last for long periods of time. [16] Film has been made on a variety of materials, including nitrate-based film stock (see: Nitrocellulose) and acetate-based film stocks, and polyester-backed film. [8]
The acetate base of the film degrades into acetic acid under non-ideal conditions, causing what is known as vinegar syndrome. Redox is the oxidation of the surface of the film and is often found in higher humidity areas. Regardless of temperature, blemishes (REDOX) appear on film and are caused by oxidation of materials stored with or near film.