RE: Black Cat Carbon Tissue

Dick,

That is correct, and I alluded to the fact in my
previous message when I wrote, "Reducing the
amount to 15g of Black Cat per 1000 ml allows
light to penetrate almost all of the way through
the
tissue, so when you strip off the tissue during
development there is only a very thin layer of
pigmented gelatin left."

The key to knowing you are using most of the
thickness of the tissue is indeed, as you say, a
thin residual image on the tissue. The thin
residual image lets you know that your procedures
are optimizing relief..

Sandy

At 12:43 PM -0700 12/22/06, Richard Sullivan wrote:
> Sandy,
>
> This is a question more than a comment. I think a good indicator of how
>deep you are going into the tissue is the residual image left on the tissue.
>As I think about it, the more detailed and brighter the image on the tissue
>backing the deeper you have gone. Real thick tissue with a lot of pigment
>will show no backing image. I think ideally you should make a thick tissue
>and lightly pigment it, adjust the contrast sensitizing, and print until
>just a very faint ghost of an image is showing on the backing.
>
>
>
> Comments please.
>
> --Dick
>
>
>
> -----Original Message-----
>From: owner-carbon@spitbite.org [mailto:owner-carbon@spitbite.org] On Behalf
>Of Sandy King
>Sent: Thursday, December 21, 2006 8:13 AM
>To: carbon@spitbite.org
>Subject: RE: [carbon] Black Cat Carbon Tissue
>
> Again, Loris has explained it correctly. The
> theory is that you will get more relief with a
> very thick tissue that has the amount of pigment
> balanced so that on exposure the light can
> penetrate all the way to the bottom of the layer.
> Of course, it is not just the tissue that enters
> into the equation as you also have to start with
> a negative of the right density range and use the
> right amount of sensitizer to optimize the relief
> effect. You can do this in various ways, but the
> most efficient way is to start with a negative
> that has a fairly high DR, say at least log 1.8 -
> 2.0.
>
> The balance between too little and too much
> pigment is a very fine one. For example, with my
> method of work using 20g of the Black Cat ink per
> 1000 ml of glop gives a tissue that allows the
> light to pentrate only about half way through the
> tissue on exposure. You can tell this is the case
> because when you strip off the tissue during
> development there is a huge amount of pigmented
> gelatin left on the tissue that did not get used
> in making the image. Reducing the amount to 15g
> of Black Cat per 1000 ml allows light to
> penetrate almost all of the way through the
> tissue, so when you strip off the tissue during
> development there is only a very thin layer of
> pigmented gelatin left.
>
> Using the frame it is no harder for me to make
> thick, lightly pigmented tissue than it is to
> make thin, heavily pigmented tissue.
>
> One of the great disadvantages of thick but
> lightly pigmented tissue is that the dichromate
> sensitizer must be reduced in strength and this
> increases exposure times significantly. If you
> use a strong dichromate the color of the
> dichromate itself, in the absence of pigment,
> will restrict the hardening action to the very
> top of the tissue, and with a thinly pigmented
> tissue you will get an image with very low Dmax. T
>
> Sandy King
>
>
> At 2:04 PM +0200 12/21/06, Loris Medici wrote:
> >The advantage is pronounced relief effect (as long as you also carefully
> >balance pigment amnt. - allowing the exposing light to reach as deep as
> >it can - but without hardening the tissue right to the bottom). The
> >disadvantage is long drying times. Also, manufacturing thick tissue
> >(with light pigment load) is harder than manufacturing think tissue
> >(with heavy pigment load) - you have to use frames to hold the glop in
> >place until it sets...
> >
> >That what comes in my mind quickly and I'm sure there are many other
> >issues to mention...
> >
> >Regards,
> >Loris.
> >
> >-----Original Message-----
> >From: Damiano Bianca [mailto:damiano.bianca@gmail.com]
> >Sent: 21 AralÏk 2006 Pers¸embe 13:42
> >To: carbon@spitbite.org
> >Subject: Re: [carbon] Black Cat Carbon Tissue
> >
> >
> >ok, my mistake was thinking 0.015. As i wrote, usually i use 0.6 / 0.8
> >mm. Now what is the the advantage with 1,55 mm? may be because the
> >"papier tissu" is not so charged in pigment?
> >
> >dam
> >
> >
> >2006/12/21, Loris Medici <mail@loris.medici.name>:
> >> Damiano,
> >>
> >> 1ml per square inch would give around 1.5mm wet height. See below:
> >>
> >> Sandy's using 1ml (1 cubic mm) glop per square inch ->
> >>
> >> If 25.4mm x 25.4mm x (WH) mm / 1000 = 1 cubic mm
> >> Then WH = 1.55mm (WH = Wet height)
> >>
> >> Regards,
> >> Loris.
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Received on Fri Dec 22 13:19:15 2006