Hardened = Tanned ?

Discussion in 'B&W: Film, Paper, Chemistry' started by dancqu, Jun 10, 2005.

  1. dancqu

    dancqu Member

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    Helen B. provided some insight into the 'pink' hangover.
    I think she is suggesting that a tanned emulsion may be as
    difficult to wash clean as a hardened emulsion. Are tanned
    and hardened gelatins, in effect, the same thing? Dan
     
  2. avandesande

    avandesande Member

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    Tanning is proportional to the negative density. If you look at a negative at an angle you will see a 'puckered' effect along the edges of high contrast. This is tanning.

    There are two ways that a film is hardened.
    1)Most modern films have a protective coating on the negative to keep it from getting scratched. Some of the old school eastern european/chinese films that are available today don't have a protective layer.

    2)Another way a negative can be hardened is with a hardening fixer. This has some sort of alumninum salt that binds to the gelatine.

    I think that tanning may effect washing but not in the same way that a hardening fixer would.

     
  3. jjstafford

    jjstafford Inactive

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    I thought tanning referred to a treatment of to an animal product, which in this case is the gelatin.