[alt-photo] Re: pigment problem

[Ian Hooper]

Try adding a small amount of acetic acid (white vinegar) to your 
gelatin/aldehyde mix. Hardening with formalin or glut is greatly accelerated 
by alkaline conditions, so tipping the pH slightly may give you more working 
time.

-Ian
----- Original Message ----- 
From: "Julian Smart" <juliansmart at virginmedia.com>
To: "The alternative photographic processes mailing list" 
<alt-photo-process-list at lists.altphotolist.org>
Sent: Tuesday, February 08, 2011 2:15 PM
Subject: [alt-photo] Re: pigment problem


> Katherine,
>
> This is the problem with the gelatine- it is literally hardening too fast 
> for me to apply over 4 sheets. The first two sheets seem to go fine, the 
> 3rd sheet shows some signs of not absorbing the geltine well (prints made 
> on this sheet work well, though the unevenness is effectively extra sizing 
> in localised areas of the paper). The emulsion still adheres to it well 
> and usually by the final coat there is no sign of any unevenness. The 
> fourth sheet will coat much the same as the third but towards the point at 
> which I think it is finished, the brush starts pulling tiny bits of 
> hardened gelatine off the paper. The gelatine is kept in the pan of hot 
> water  in between coatings and does not appear to thicken over the 20 or 
> so minutes it takes me to size four 1/2 imperial sheets.
>
> I have not had problems printing on  paper sized/hardened this way with 
> any pigment (or mix of pigments- I know W+N Indigo is a cocktail) other 
> than The Indigo mentioned. I am about to try a coat of Indanthrene Blue, 
> PB60 at the usual shadow coat dilution as a control- watch this space  ;~)
>
> Julian.
>
>
>
> ----- Original Message ----- 
> From: "Katharine Thayer" <kthayer at pacifier.com>
> To: "The alternative photographic processes mailing list" 
> <alt-photo-process-list at lists.altphotolist.org>
> Sent: Tuesday, February 08, 2011 2:51 AM
> Subject: [alt-photo] Re: pigment problem
>
>
>> P.S. On second thought, it sounds like what you're saying is not that 
>> the gelatin is cooling and gelling, but that it's hardening before it 
>> gets brushed on, which is a different issue.   In which case, maybe 1 
>> drop formalin instead of two?  But I'd check first and make sure it's 
>> not that it's cooling down and setting up; that's the easier problem  to 
>> solve.
>>
>>
>
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