[alt-photo] Re: Dichromated Gelatin Formula

[etienne garbaux]

Gord wrote:

>Could using different more malleable metal than lead support an 
>easier way of making Woodburytypes?  Aluminum is more 
>malleable.  Could a stack of aluminium foil work?

Woodbury used tin foil for the related stannotype process, and also 
experimented with plating the gelatin (today, one might use 
electroless nickel plating).  But again, the lack of extreme pressure 
used in making the molds made them very different in appearance from 
Woodburytypes.  Where Woodburytypes have very smooth tonal gradation 
due to the extreme pressure, stannotypes and all of the modern 
attempts to simulate Woodburytypes with casting processes yield very 
much noisier tonal gradation -- the opposite of a Woodburytype.  The 
Eastman House had a few stannotypes in the archives, but since the 
process never caught on commercially they are very rare.

(A related phenomenon plagued all attempts to reproduce vinyl records 
with optical sensors.  The diamond stylus of a mechanical pickup does 
not play the surface of the groove -- rather, it "swims" through tens 
of micrometers of the vinyl under the enormous pressure on the 
diamond contact points, so the defects on the groove surface are attenuated.)

Best regards,

etienne