[pure-silver] Re: Cleaning a Drum Dryer

Hi,

When I was doing the sepia toning, it was written on the instructions that a hardener should be used after toning because the bleaching process renders the paper soft. Do they mean that the bleach "eats" away the protective layer of gelatin coating in order to get at the emulsion?????

I did not use a hardener and noticed that on several of my prints, there were motes of dust imbedded in the paper. I took one print and tried to rub off the dust but to no avail. That's when I realized that it was imbedded in the paper, but which layer, emulsion layer or was there still some gelatin left, despite the bleaching?

Cheers,
Bogdan

Richard Knoppow wrote:

snip


The Baryta layer _is_ a coating of gelatin. It is the sizing for the paper. Most papers have more than one layer but the number of layers also has to do with what sort of texture the paper is to have. Note that there is a difference between texture and surface: texture is gotten by callendering the paper before the emulsion is coated and texture is usually from something in the overcoating (like talc). Generally fiber paper has three basic coatings: the baryta layer, the emulsion coated over this, and a protective layer of gelatin coated over the emulsion. This protective layer is what is used to obtain the very smooth surface when ferrotyping. Dave Valvo, who is on this list, is a former Kodak paper expert and can unboubtedly provide more complete information.

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Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx


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--
________________________________________________________________
  Bogdan Karasek
  Montréal, Québec                     bogdan@xxxxxxxxxxxxxxx
  Canada                               www.bogdanphoto.com

                  "I photograph my reality"
________________________________________________________________


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