Re: Watercolor pigments - pigments to avoid...

Hi Dave, I agree in theory that hardening the internal sizing first
might eliminate the problem, but I'm not sure I see the necessity
of adding another step, when it's simple enough to watch the
temperature and keep the gelatin warm enough to brush easily, but
cool enough not to cause problems. But yes, hardening the internal
sizing should make the paper more stable to hot water. But at the
same time I have this vague recollection that someone tried it once
and it didn't work as well in practice as in theory. I don't
remember the particulars, and maybe I only dreamed that.

  I've been in the moving process for three months now and still a
long ways from being unpacked and settled in, so when someone says
they are going to move, my first thought is "Horrors! Don't do it!"
My sympathy,
Katharine

On Jul 13, 2006, at 9:01 AM, Dave Soemarko wrote:

> Hi Katherine,
>
> I agree (and it makes sense) that if the paper is sized with
> gelatin, then
> the higher your gelatin bath is, the more likely it is going to cause
> trouble.
>
> You can use gelatin bath with a more controlled temperature, as you
> did, or
> maybe you can try hardening the paper itself first (more accurately,
> hardening the internal sizing of the paper first). Then when you add
> external sizing yourself, the temperature is less critical. I don't
> know
> whether it will work, and I don't know which one is actually easier
> (for me,
> I think sizing all the paper once, perhaps after purchase, doesn't
> seem to
> bad), but it might be worth a try to see if it works and/or to gain
> some
> insight to the internal sizing.
>
>
> Dave
>
> PS: I still cannot make any gum print right now. I am hoping to
> move to a
> new place this summer, but currently I am only in the process of
> searching
> for the new place....
>
>
>> -----Original Message-----
>> From: Katharine Thayer [mailto:kthayer@pacifier.com]
>> Sent: Thursday, July 13, 2006 11:34 AM
>> To: alt-photo-process-l@usask.ca
>> Subject: Re: Watercolor pigments - pigments to avoid...
>>
>>
>> On Jul 13, 2006, at 7:59 AM, Christina Z. Anderson wrote:
>>
>>
>>>> You heated the gelatine to a point where you destroyed its
>>>>
>> qualities
>>
>>>> as a size..
>>>> Forget the formalin.
>>>> Terry
>>>>
>>>>
>>>
>>> Terry,
>>> I respectfully disagree. I know this isn't good practice, but to
>>> prove a point I boiled my gelatin and lived to tell the tale. Even
>>> gelatin boiled for 20 minutes worked fine as a size on
>>>
>> about 60 large
>>
>>> gums. No speckle, no stain, no nuttin'. For me, this was another
>>> myth down the drain that you had to watch the temp of gelatin while
>>> heating it up. Or, at the very least, I don't sit there with a
>>> thermometer anymore watching the pot not boil. But, as they say,
>>> YRMV.
>>>
>>
>> And my own tests show something different from what either of
>> you are saying, I think... my own tests show that it doesn't
>> matter if the gelatin has been boiled, as long as it's
>> relatively cool when it's applied, and furthermore applying
>> the size while hot may only be a problem with some papers.
>> Arches papers, which are internally sized in a gelatin bath,
>> go speckly on coating with gum if the temperature
>> of the sizing was over 140 when applied, IME. But if the same too-
>> warm gelatin is cooled to 140 and then applied, no speckles
>> happen. I suppose that what happens is that the too-warm size
>> partially melts and disrupts the internal sizing, affecting
>> the behavior of the
>> paper. I haven't tried this with papers sized with non-gelatin
>> material, but from reports that it's not a problem with such
>> papers, I am willing to tentatively conclude that this isn't
>> a universal problem, but only affects some papers, most
>> likely those with a factory gelatin size.
>> Katharine
>>
>>
>>
>
>
>
Received on 07/13/06-10:29:02 AM Z