RE: Black Cat Carbon Tissue

  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 Aralžk 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 12:57:15 2006