# clearing film



## wayward bob (Oct 7, 2011)

is there an easy/quick way to clear colour film? i seem to remember keeping offcuts to test b&w paper chemistry - i think it was for the fix? but i don't remember whether that was b&w or colour film.


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## Hocus Eye. (Oct 7, 2011)

With black and white fixer, you can test whether or not it is exhausted by dipping a piece of unprocessed black and white film in it. Then you 'fix for twice the clearing time' in the old saying. If the clearing time is longer than expected, dump the fixer. You could use unprocessed colour film as well.

Is that what you are referring to or something else? It won't work with processed film though. Processed colour film has the silver particles turned to dye.

I suppose you could bleach the dye in colour film to remove it if you just want a clear piece of acetate.


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## wayward bob (Oct 7, 2011)

i'm talking about unprocessed film. so fix will work on colour? any other cheaper household chemicals do the same job?


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## Hocus Eye. (Oct 7, 2011)

wayward bob said:


> i'm talking about unprocessed film. so fix will work on colour? any other cheaper household chemicals do the same job?


Basic fixer is Sodium Thiosulphate. That is the old fashioned slow fixer often called 'hypo' in photo labs. It comes usually ready-mixed as a solution in water or as crystals which you add to water. It has some uses in medicine so perhaps it can be got from a chemist. Modern Rapid Fixers eg Ilford Hypam are a different chemical and are more expensive. Hypam is stocked by Jessops and costs about £10 a litre which you dilute 1 + 4 with water.


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## wayward bob (Oct 8, 2011)

i'm sure i have fix in a cupboard somewhere. bit old so no loss if i try it and it doesn't work. cheers


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## Hocus Eye. (Oct 8, 2011)

wayward bob said:


> i'm sure i have fix in a cupboard somewhere. bit old so no loss if i try it and it doesn't work. cheers


It doesn't go off so you should have no problems


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## Stanley Edwards (Oct 8, 2011)

What exactly are you trying to do?

If you want a roll of film with blank, clear frames, the easiest way is to shoot a roll of B&W with the lens cap on and then process as usual.


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## wayward bob (Oct 8, 2011)

Stanley Edwards said:


> If you want a roll of film with blank, clear frames, the easiest way is to shoot a roll of B&W with the lens cap on and then process as usual.



yeah but that involves several chemicals, whereas just dunking it in fix is a load quicker/easier  but yeah, i just want clear(ish) film.


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## Stanley Edwards (Oct 8, 2011)

OK. Just bleach it in fix then. I think normal household bleach will bleach the frames also possibly??? Not sure. Colour film has a slight tint. B&W will give much clearer clear!

What you gonna do?


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## wayward bob (Oct 8, 2011)

don't know yet


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## Hocus Eye. (Oct 10, 2011)

Yes colour film has an orange layer. Black and White film also has a very light grey tint caused by the anti-halation dye. This can be removed with bleach after fixing it if you really want it to be as clear as glass, but you probably don't need to go that far.


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## wayward bob (Oct 10, 2011)

while i'm here - anyone know the melting point of film?


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## Stanley Edwards (Oct 10, 2011)

wayward bob said:


> while i'm here - anyone know the melting point of film?



It probably combusts before it melts!

Try Googling 'flash pont', or something similar. Film projectors get very hot. I suspect film has some sort of fire retardent chemical added to the acetate along with all the other chemical light reactive layers.

Unless of course you mean melting the film in a solution. Then I would guess about 40 degrees before the layers fall off the acetate.


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## Hocus Eye. (Oct 11, 2011)

Stanley Edwards said:


> It probably combusts before it melts!
> 
> Try Googling 'flash pont', or something similar. Film projectors get very hot. I suspect film has some sort of fire retardent chemical added to the acetate along with all the other chemical light reactive layers.
> 
> Unless of course you mean melting the film in a solution. Then I would guess about 40 degrees before the layers fall off the acetate.


As Stanley says, the emulsion layer will melt at a much lower temperature than the acetate base. The emulsion is gelatine. If you put it in very hot water it will separate from the base as it dissolves. The acetate base will have a very high melting point but I have no idea what it would be. Why would you need to know?


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