[pure-silver] Re: Here's one for the head scratchers
- From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
- To: <pure-silver@xxxxxxxxxxxxx>
- Date: Sun, 16 Jan 2005 19:51:09 -0800
----- Original Message -----
From: "Helen Bach" <helenbach@xxxxxxxxx>
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Sunday, January 16, 2005 7:24 PM
Subject: [pure-silver] Re: Here's one for the head
scratchers
>A thousand apologies for the misinformation about
>Autographic film,
> and many thanks to Richard for pointing out my error.
>
> Here's something from a 1915 Kodak publication:
>
Its possible this would also work by pressure on ordinary
film. I have an Autographic camera but it takes a long
discontinued size of film. Plus it has holes in the bellows.
Too bad.
N.C. BTW, stands for Non Curling. This film had a coating
of gelatin on the back to counteract the curling caused by
differential shrinking of the emulsion. I am not certain
when N.C. film was introduced, perhaps before 1920. A little
research will find out. All roll film is back coated. For
many decades the backcoating of black and white negative
film has included an anti-halation dye. This dye is either
removed or changed to a colorless state by the sulfite in
the developer and fixing bath. The introduction of the
backcoating was evidently a considerable improvement: early
roll films evidently curled very severely.
Modern color films have their anti-halation coating in
the form of a layer under the emulsion, which, like the back
coating, is decolorized during development.
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx
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