Hardened = Tanned ?

[dancqu]

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

 

[avandesande]

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.

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

 

[jjstafford]

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.
.

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