Re: Gum woes revisited

Hi David,

Generally I brush coat about 100 sheets of 7-1/2x11 paper at a time so I mix
up only enough size for that quantity of paper, about 600ml. I mix my size
in a glass Pyrex measuring cup. I take 600ml of distilled water at room
temperature (65-68F) and evenly sprinkel 20gm of Knox gelatin over it, allow
it to soak for 15 minutes, then heat it to between 120-140F on a portable
electric burner. While the gelatin is heating, I mix 2gm of chrome alum in
30 ml of distilled water and bring it to the same temperature as the gelatin
or a bit hotter. When both solutions are about 120-140F, I slowly pour the
chrome alum into the gelatin with constant stirring. For coating, I take a
1/3 of the mix in a separate glass beaker, putting it on a candle warmer
(like a coffee hot plate), and leave the rest on the electric burner on low.
I use a cheap ($0.50) chip brush from the paint store to apply the size; one
dip of the brush is enough for my paper size. I get more size from the
larger cup as needed. I brush it on in vertical strokes, then smooth it out
with horizontal and vertical strokes. I don't worry about air bubbles in the
coat, after sitting for 10 minutes they disappear. I then hang the paper to
dry overnight before applying a second coat. I've never had any problems
with doing it this way except for needing a second coat for certain
processes.

Hope this helps, Scott

swphoto@verizon.net

----- Original Message -----
From: "davidhatton" <davidhatton@superonline.com>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Friday, May 20, 2005 3:31 PM
Subject: Re: Gum woes revisited

> Hi,
>
> How did you actually mix this? I tried the recipe and the litre of
> gelatine turned to flubber within 2 mins...!
>
> Regards
>
> David Hatton
Received on Fri May 20 21:24:33 2005