Re: Monochrome pigment tissue on polyester support

Peter charles fredrick (pete@fotem.demon.co.uk)
Fri, 26 Jan 1996 13:29:22 +0100

>Stefen
>
>>I coated a few sheets of (pre-sensitized) monochrome pigment tissues using=
>>polyester (Mylar-D 0.075 mm) as a support instead of paper.
>
>There are a lot of advantages following this method
>
>
>:> Dichromate does not penetrate the support and you need no gloves when
>> touching
>
> It is always good chemical hygiene to wear gloves if you can stand them !
>
>
>>The problem is the processing after exposing the tissue as usual
>>plastic support prevents the hot water from the gelatin.
>
>I can see that this could be a problem, a suggestion I would like to make
>is to use a pricking tool, such as used in dry mounting plastic overlays
>and laminates so that the mylar is impregnated with numerous tiny holes,
>which should help to alleviate this problem
>
>>Does anyone use plastic supports for monochrome work or would you call me
>a fool ? :-))
>
>You are no fool Stefen, my good friend Mike Shorter recently wrote an
>article in
>A.P.R.2 entitled, Carbon Tissue Making, in which he described a method very
>similar to your own.
>
>
>
>Hope this helps pete

>able to penetrate through the plastic to the gelatin, and Peter Charles
>suggestion that you solve this problem with tiny perforations, both miss
>the real point, that is, the tissue simply received too much exposure
>for its specific opacity.

Stefen

After reading sandy's reply to your problem it seems that I may have misled you
I have checked with Mike shorter and he agrees with Sandy that the probable
cause of your trouble is under pigmentation.Thinking and doing are not
always the same thing, as I have found out to my cost on other
occasions.Mikes formula may be of some use to you it is:---

Gelatin Coat Plasticiser

Distilled Water 460ml Distilled Water (hot) 20ml
Gelatin 28g Sugar
20g
Plasticiser 15ml Gum Solution 150ml
Pigment as Glycerine
30ml
Indian ink 12ml Tween 20
10drops

He uses Frisk Polydraw .002 double matt drafting film,and spray starches
before use

I hope this really helps
pete

Sandy, who's the Master now,you are. :-))

pete