Re: Boiling gelatin

From: "Katharine Thayer" <kthayer@pacifier.com>
> In the interest of that grand database that we're all building together,
> I'm curious about your method; did you boil the gelatin and then cool it
> and apply it at a cooler temperature, or did you apply it very hot?

I boiled it for a really long time, then had to go somewhere so it cooled
and then I reheated to boiling, added the glut, and brushed it on very hot.
I have it in a thermos, so I pour out a 1/4 cup at a time into a container
and use that.

I would surmise from experience that the speckling is paper related, and not
necessarily a factor of boiling gelatin, and certainly could have to do with
the paper's internal manufacturer size.
Chris

> To my mind this speckling problem that I've seen occurring with hot size
> is not about whether gelatin has been boiled or not that makes the
> difference, but the temperature on application. And again, let me repeat
> that for all I know this may not be the same for all papers or for all
> hardeners. But what I suspect is that it's not about how hot the gelatin
> is, but how hot the water is; in other words I'm thinking the speckling
> effect that I've seen with hot (never boiling) gelatin size, on Arches
> papers, with no size and with gelatin-gesso size, doesn't have anything
> to do with the gelatin per se. The same thing might happen if you just
> treated the paper with hot water. What I suspect happens is that the
> hot water does something to the factory size on/in the paper; since the
> temperature of the water is above the point where gelatin dissolves, it
> just may be that the hot water dissolves some of the gelatin size that's
> in the paper, and that this is what causes the failure of the size
> later.
>
> And if my speculation has any merit, then it would make sense that I
> would see the effect in Arches paper, since it is factory-sized with
> gelatin, and that Chris wouldn't see the effect in Fabriano Extra-White,
> since it is not factory-sized with gelatin but with some other substance
> which is most likely not subject to the same disruption. What do you
> think? It makes a whole lot of sense to me,
Received on Sat Mar 12 09:48:03 2005