Re: B&S Carbon Tissue, was Re: Gum on Azo?

The pigment used is a reddish/brown iron oxide. It has been traditionally
been this color so that:

1.) It limits the diffusion of light within the gelatin layer during
exposure. As far as the gelatin and dichromate are concerned, iron oxide,
ground fine enough, is chemically inert and has little effect on the overall
function of these ingredients.

2.) As Sandy states, this enables the worker to visually see progress under
various illuminations ( red, yellow and daylight) and to also to monitor the
progress of etching through the gelatin stencil.

There are other ingredients which are added to Autotype tissue to give it
pliability and to act as preservatives. They also modify the working
qualities of their tissue by offering two grades, a normal or "flat"
contrast (G25) and a high contrast (G35), by using a different bloom of
gelatin. All of these are proprietary formulas.
They come in different length and width rolls, so the $350.00 price was
obviously a big one.
Cheer, Craig Z.

----- Original Message -----
From: Sandy King <sanking@clemson.edu>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Saturday, December 06, 2003 10:45 AM
Subject: Re: B&S Carbon Tissue, was Re: Gum on Azo?

>
> As far as I can determine Autotype tissue is just carbon tissue with
> a funny color. But the color apparently has some importance for
> gravure workers because it allows one to visually interpret the
> density of the relief positive. In the chapter I did on tissue making
> for David Morrish and Marlene MacCalum's book Copper Plate
> Photogravure I did a lot of testing in an attempt to provide a
> formula that would give a tissue similar in color and contrast to the
> Autotype tissue. However, I know someone who uses regular carbon
> tissue for gravure work so having the same color is obviously not an
> essential part of the process.
>
> There are also some differences in speed and development requirements
> (time and temperature) between Autotype and B&S tissue but this
> should be no problem for someone who knows how to control the
> materials.
>
> BTW, you mention a price of $305 for a roll of the Autotpe material.
> How much is that per square foot?
>
>
>
> Sandy
>
>
>
> >Sandy King wrote:
> >
> >> Gregory W. Blank wrote:
> >>
> >> >on 12/2/03 6:31 PM, Sandy King at sanking@clemson.edu wrote:
> >> >
> >> >> because B&S is about to offer on a commercial basis
> >> >> carbon tissue, perhaps as early as February or March of 2004.
> >> >> Sandy King
> >> >
> >> >That is awesome.
> >>
> >> Is it not so?
> >>
> >> And the product is very good. I have been testing prototype B&S
> >> carbon material off and on for about 1.5 years, and quite intensely
> >> during the last 3-4 months. I also did a review of the material for
> >> View Camera which should appear in a very recent number, perhaps
> >> Jan/Feb of 2004. And check the B&S website for information as to when
> >> it will be commercially available.
> >>
> >> Sandy
> >
> >This is indeed potentially great news. Do you know, will this carbon
> >tissue work for copper plate photogravure? As of now, there is only one
> >source of carbon tissue suitable for photogravure (that I know of), from
> >Autotype, for $350 a roll!
> >
> >J. Reisland
>
Received on Sat Dec 6 14:45:10 2003