Film Deterioration Guide. It is important that the film archive community uses the same terminology when referring to deterioration on film. The Technical

Film Deterioration Guide


It is important that the film archive community uses the same terminology when referring to deterioration on film.

The Technical Commission is producing a series of posters to help in the identification of these deterioration.This project is called Film Deterioration Guide.The first poster is about the Cellulose Nitrate Decay.


The first impression on the technical state of a filmis made when we look at its reel.Rewinding the film we observe how it behaves.Looking closely at it with a magnifying lenses we gatherImportant information.The posters will have images covering these various levels of observation so that in case of doubt more than one situation is offered as example.


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Cellulose nitrate is an unstable polymer.Its decomposition starts when the polymer is manufactured and continues until total destruction of the film.Cellulose nitrate is highly flammable.Some cellulose nitrate survived for more than 100 years in quite good condition.Nitrate prints have an unique “look” and film archivists love it.


5 stages of Cellulose Nitrate decomposition:

a. All starts with a “sweet” smell;

b. Slight discolouration of the plastic (film base);

c. Followed by the bleaching of the silver image;

d. The emulsion medium (gelatine) breaks down onto a viscous paste;

e. In the final stages film congeals onto a solid block and then become

a brownish powder.

(*) Up to the stage d film content can be recovered.


1Structure of the poster,each category is displayed as:

1. Reel format2. Reel on a rewinder plate3. Detail of the deterioration4. Film between plates on a rewinder5. 3 frames in real size (1:1)6. 10X magnification

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1Image discolouration 1

The gases released by cellulosenitrate decomposition react withthe silver forming the black andwhite image fading and bleaching this image.The first signs are a metallic shinefollowed by the yellowing of theImage.


Image discolouration 2

Image discolouration can reach drastic levels.Cellulose nitrate decomposition canrelease other chemicals (plasticizer)that will appear in the surfaces of thefilm as finely divided solid deposits.


1Base discolouration

Chemical changes in the cellulose nitrate molecule modify the way it interacts with light making the film base no longer transparent.Base discolouration can go from yellow to dark brown with a variety of colours in between.


1Emulsion breakdown 1

Gases released by cellulosenitrate decomposition react withmoisture and form acids thatreact with the gelatine (emulsionmedium) making it become liquid.In an initial stage of this deterioration film can still be saved.


In the last stages of decompositioncellulose nitrate film cannot berestored.

Special personal protection equipment must be used to handle film in this stage of decomposition.


2. Cellulose Acetate(s) Decay


1Base Limpness

Gelatine breakdown produce, In advanced stages, massivedeterioration on film.



1Base Limpness




1Base Curling




1Base Curling




1Plasticizer Liquid Residues




1Plasticizer Solid Residues



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Documents

Film Deterioration Guide. It is important that the film archive community uses the same terminology when referring to deterioration on film. The Technical