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 07/13/06-09:32:44 AM Z
This archive was generated by hypermail 2.2.0 : 08/31/06-12:23:48 PM Z CST