[alt-photo] Re: A PVA postscript

[Paul Viapiano]

Just as an anecdotal aside FYI...when I acidify Fab EW for pt/pd printing, I 
use lukewarm water and the paper sits in the oxalic acid bath for 3 minutes 
only. After drying I have found that the paper is preshrunk enough for fine 
registration of pt/pd printing and associated multi-layer gum-overs, or even 
a second exposure of pt/pd. That 3 minutes in lukewarm water is 
enough...sometimes I even use the acidified paper for tri-color gum, and it 
works fine.

Paul


----- Original Message ----- 
From: "Diana Bloomfield" <dhbloomfield at bellsouth.net>
To: "The alternative photographic processes mailing list" 
<alt-photo-process-list at lists.altphotolist.org>
Sent: Friday, April 02, 2010 10:13 AM
Subject: [alt-photo] Re: A PVA postscript


> Oh, I see.  Thanks.  I just saw Jeremy's post.  I use lukewarm water, 
> too, and just let it soak for a long while, while I go do something  else. 
> I've never used super hot water, but a few people have posted  that using 
> really hot water does something to that internal sizing, so  everything 
> becomes sort of mottled (?).
>
> Diana
> On Apr 2, 2010, at 1:31 PM, Henry Rattle wrote:
>
>> In my case, it wasn't a good idea because I normally pre-shrink - so
>> shouldn't have taken a shortcut by doing the tests without the 
>> preshrink. I
>> used to be a scientist - should know better!
>>
>> Best
>>
>> Henry
>>
>>
>> On 02/04/2010 16:28, "Diana Bloomfield" <dhbloomfield at bellsouth.net> 
>> wrote:
>>
>>> Thanks for the update, Henry.  So when you say using PVA on paper  that
>>> hadn't been pre-shrunk was not a good idea-- is that because there  was
>>> too much internal sizing in the paper, so hard to coat the PVA, or
>>> that just meant too much sizing overall, and everything washed off?
>>>
>>> I have to admit, I never had a lot of luck with the PVA, or was very
>>> happy with the results using PVA-- except on BFK Rives paper (in all
>>> its varied forms/weights).  I think you'd probably like that if you
>>> gave it a try.
>>>
>>> Interesting.  Thanks again.
>>>
>>> Diana
>>> On Apr 2, 2010, at 1:08 PM, Henry Rattle wrote:
>>>
>>>> My first, reasonably successful, trials of PVA as a size for
>>>> tricolour gum
>>>> were carried out on paper which had not been preshrunk. Not a good
>>>> idea, as
>>>> it turns out. Moving on to using Gamblin PVA at 1+1 dilution for
>>>> prints on
>>>> preshrunk paper, I find that while Fabriano Artistico (cold-press,
>>>> traditional white) still works reasonably well, my favourite  Saunders
>>>> Waterford HP reacts badly. After preshrinking under mild conditions
>>>> (1 hour
>>>> in water at 25C) first gum (yellow) coat seems to work OK, but the
>>>> subsequent (magenta) coat is horribly blotchy and clears very badly
>>>> and
>>>> unevenly. Looks as though internal sizing has washed out so that the
>>>> PVA
>>>> doesn't go on evenly. A control with gelatin sizing looks fine with
>>>> the same
>>>> coating and treatment.
>>>>
>>>> Wonderful stuff, gum - just one variable after another...
>>>>
>>>> Best wishes
>>>>
>>>> Henry
>>>>
>>>>
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