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-Film '''base''' is the material that film emulsion is printed on. It is sometimes referred to as the "support" as it is the supporting material that the emulsion layer is then coated on. You may need to handle prints differently in exhibition settings and in long term storage depending on the material their base is made of.
+Film '''base''' is a type of flexible material used as a foundation or base for film [[film emulsion]]. Film emulsion is made up of light sensitive silver halide grains suspended in a gelatin coating. Film base is sometimes referred to as the "support" as it is the supporting material that the emulsion layer is then coated onto. Throughout history it has been made of different materials, all of which require different handling techniques for projection as well as storage.
-*A note about the use of the term "film stock" in this article. People often use "film stock" interchangeably with "film base" to refer to the physical material upon which the film is printed as identified by the composition of the "film base". This is a colloquial use of the term. The proper use of [[film stock]] is to refer to film manufactured by a specific film lab, or that is associated with specific properties of the emulsion like color saturation or development speed etc. For example, you might say "this film was printed on black and white Orwo stock" or "Kodak 2383 stock".
+*A note about the common usage of the term "film stock". People often use "film stock" interchangeably with "film base" to refer to the physical material upon which the film is printed as identified by the composition of the "film base". This is a colloquial use of the term. The proper use of [[film stock]] is to refer to film manufactured by a specific manufacturer, or that is associated with specific properties of the emulsion like color saturation or development speed etc. For example, you might say "this film was printed on black and white Orwo stock" or "Kodak 2383 stock".
 ===How to tell the difference between the base side and the emulsion side===
-The base side of a print will look shinier, the emulsion side more matte and you can often see the raised edges within the frame where the emulsion is thickest. Using a flashlight, move the film back and forth and observe how the light reflects off the surface. It is easier to tell which side is which more on certain prints than others. Black and white prints are often the easiest, very worn prints or newer color prints can be difficult.
+The base side of a print will look shinier and the emulsion side will appear more matte.Using a flashlight, move the film back and forth and observe how the light reflects off the surface. On the emulsion side you can often see the raised edges within the frame where the emulsion is thickest. It is easier to tell which side is which with certain prints more than others. Black and white prints are often the easiest, very worn prints or newer color prints can be difficult.
 ===Why is it important to know what film base a print has?===
 * '''For Projection:''' Only venues who are properly equipped to project nitrate film should do so. Many projectors require gate tension adjustments between prints that are polyester and acetate the latter is slightly thicker. This difference in thickness also means adjustments in focus must be made if acetate and polyester films are spliced together in a single reel (such as a trailer reel).
 * '''For Storage:'''Nitrate and acetate films have very specific needs with regard to long term storage. Improper storage can lead to deterioration of the film base.
+* Acetate tends to become more brittle with age and may require gentler handling
+* Knowing the type of film base can help you determine when the print was manufactured.
 ==Types of Film Bases==
-===Polyester===
-With rare exceptions, all 35mm release prints made since the late 1990s have been printed on '''polyester''' base. Many 16mm prints from the mid 80s onward are also printed on polyester. Nothing pre-1955 will be on polyester base. Unlike acetate or nitrate, polyester is essentially unbreakable and cannot be torn by human hands. It is also not susceptible to vinegar syndrome and does not warp or shrink (though it is not uncommon for the film to have a slight "bow"). Polyester base is easy to identify because it is slightly thinner than acetate or nitrate. Polyester film cannot be cement spliced - it must be tape spliced or ultrasonic spliced.
-* Polyester film is often referred to as "Estar base" which is the Kodak trade name for the polyester base that they manufacture.
-===Acetate===
-[[File:Acetate_note.jpg|300px|thumb|righ|A handling note found on a 35mm acetate print from Universal]]
-Used in the early 1930s mostly for small gauges, then was widely used post 1950s to replace nitrate base. Often refered to as "safety film". Acetate" base in modern exhibition settings usually refers to '''triacetate''' base. '''Diacetate''' was used on some early safety film, but you won't see it very often under normal circumstances (whatever THOSE are!). Older acetate prints tend to be more brittle and prone to warping as they lose moisture. Acetate is thicker and tends to break when stressed.
-*Introduced in 1948 as a replacement for nitrate film for 35mm prints
-*Use only tape or cement splices
-*Acetate base prints can suffer from vinegar syndrome if not stored at the proper temperature and humidity levels. Make sure they are kept cool and dry, and separate out any prints you suspect of having vinegar syndrome (even the beginning stages) as it can spread from one print to another.
 ===Nitrate===
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 *''Fun fact'':  Nitrate is made from cotton!
 A guide to identifying and handling nitrate film stock can be found here on the [https://amianet.org/wp-content/uploads/Resource-Nitrate-Identifying-and-Handling.pdf Association of Moving Image Archives website].
+===Acetate===
+[[File:Acetate_note.jpg|300px|thumb|righ|A handling note found on a 35mm acetate print from Universal]]
+Used in the early 1930s mostly for small gauges, acetate film was first used for 35mm print in 1948 in order to replace nitrate prints, and became widely used by the mid-1950s. Often referred to as "safety film" in order to differentiate it from the highly unstable nitrate film. Acetate base in modern exhibition settings usually refers to '''triacetate''' base. '''Diacetate''' was used on some early safety film, but you won't see it very often under normal circumstances. Older acetate prints tend to be more brittle and prone to warping as they lose moisture. Acetate is thicker than polyester (see below) and tends to break or snap when stressed.
+*Use only tape or cement splices, it cannot be spliced ultrasonically
+*Acetate base prints can suffer from vinegar syndrome if not stored at the proper temperature and humidity levels.
+** '''Vinegar Syndrome''' is a type of film decay where heat, water, high humidity cause the acetic acid in the film base to break down and escape. It is something that only happens to acetate film bases.
+***Signs: Film smells like vinegar. Other things like film cleaner may cause a print to "smell funny" but a vinegary smell is associated specifically with Acetate Film Base Degradation aka "vinegar syndrome". Film begins to shrink and warp, becomes less flexible and more brittle. ''Note: Acetate film prints may also become more brittle over time, but this does not mean they have vinegar syndrome.''
+***Handling: Make sure prints they are kept cool and dry, and separate out any prints you suspect of having vinegar syndrome (even the beginning stages) as it can spread from one print to another. Clean projectors thoroughly with 99.9% isopropyl alcohole after screening prints you suspect may have it. There is no reversing the process, but cold storage can halt it. See the "Resources" section of this page for more detailed information about storage of film prints and testing for vinegar syndrome.
+===Polyester===
+Developed in the ‘40s (used first in still photography and small gauge motion picture film) not widely used for 35mm motion picture till the mid ‘90s. With rare exceptions, all 35mm release prints made since the late 1990s have been printed on '''polyester''' base. Many 16mm prints from the mid 80s onward are also printed on polyester. Nothing pre-1955 will be on polyester base. Unlike acetate or nitrate, polyester is essentially unbreakable and cannot be torn by human hands, it tends to stretch rather rather than snap when stressed. Polyester base is slightly thinner than acetate or nitrate.
+* Polyester film cannot be cement spliced - it must be tape spliced or ultrasonic spliced.
+* Not susceptible to vinegar syndrome and does not warp or shrink (though it is not uncommon for the film to have a slight "bow")
+* Polyester film is often referred to as "Estar base" which is the Kodak trade name for the polyester base that they manufacture.
 ===How to tell the difference between polyester and acetate===