From: TERRY KING, 101522,2625
TO: Judy Seigel, INTERNET:jseigel@panix.com
DATE: 23/05/96 16:10
RE: Copy of: Re: Copy of: buying Gum Arabic
> Sender: alt-photo-process@cse.unsw.edu.au
>Judy
I said
> > Graphic art and printers' gum at 14 Baume works fine if you are going to
give
> > your prints a good hard size first. In general you will have greater control
You said
>
> Terry, I think that depends on the paper. Some do better with no added
> size. In fact with heavier gum in proportion of 2 parts gum to one part
> dichromate, I find no added size works better on all but the most
> absorbent papers.
That's what I have been saying all along like a voice in the wilderness, but
with heavier gum, that is why I use 17 Baume or Gloy. 14 tends to degrade the
highlights after two or three printings when one gets to the darker tones. A
good size will prevent this.
>
> > gum at 17
> > Baume . The cheapest way to buy it is in the form of white gum arabic
powder
> > from art print materials suppliers. You mix it 50/50 with cold water and let
it
> > stand to dissolve, in other words do not stir it. Here it costs about eight
> > pounds per half kilo i.e. sixteen pounds a litre for the gum. You will need
to
> > keep it in the fridge.
>
> Why not add a few drops of formaldehyde (maybe gloxal works too) or
> thymol? My home-mixed gum is a year old and still fine with formaldehyde
> added. (If someone is going to say formaldehyde in that amount is
> dangerous, they better go out & sleep on the grass because your permanent
> press sheets have probably been treated with it.)
>
I have some formaldehyde on the shelf and I would probably use it or glyoxal if
i had some but I use Gloy instead now. I have just checked and my bottle of home
made, it is OK after a year and there is no preservative in it at all.
> I'm wondering tho what (was it Francois?) meant by "higher quality gum
> arabic" being glossier. There may be a co
Well it does not sink in so much.
Terry