RE: Watercolor pigments - pigments to avoid...

Chris,

I agree with you. My experience is similar to yours.

The technical literature says that gelatin will loose its gelling property
it is repeatedly melted (at boiling point) and regelled. Since we are not
doing that repeatedly, I just use the temperature as a rough guide.

And this is how I "calculate" it: swollen gelatine dissolves at around 40C.
Boiling water is about 100C. Our body temperature is about 37C. So by feel
alone you can determine how hot it should be (I use something hotter than
warm but not hot enough to hurt myself).

In practice, if I need a fairly diluted gelatin mix, I mix the small amount
with small amount of water to let it swell, then I heat the water to boiling
point, then remove it from heat for about 3 minutes (so I know it is still
very hot but is below boiling point), then I add the hot water to the
swollen gelatin.

If I need a heavy gelatin mix, I mix the water with gelatin in a
stainless-steel bowl and then put the bowl on (in?) hot water below boiling
point as above. All this is done by "feel." I do this to avoid the boiling
point, but as mentioned, even going to boiling point didn't hurt any for me
(that is, concerning the property of the gelatin itself. The application of
it, as mentioned by Katherine, is a different issue, of course).

Dave
 

> -----Original Message-----
> From: Christina Z. Anderson [mailto:zphoto@montana.net]
> Sent: Thursday, July 13, 2006 10:59 AM
> To: Alt, List
> Subject: Re: Watercolor pigments - pigments to avoid...
>
> > 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.
> Chris
>
>
>
>
Received on 07/13/06-09:56:41 AM Z