U of S | Mailing List Archive | alt-photo-process-l | Re: Standard strength gum

Re: Standard strength gum

Dear Ed,
I did a lot of monkeying around to get a "standard" gum mix
a la 14 baume.  Depending on the gum's absorbency, it can
vary 50g per liter!  What was "standard" back in the 1890's
was a "2 in 5".  That works great.  I found that when I
mixed 24g into 84ml water that made 100ml of gum with the
powdered--not quite the 2 in 5 standard, but it works great,
too.  You don't have to be so putzy, tho--use 30 + 90, for
instance, which is a 1+ 3 or mine which is more like a 1 +
3.5 or the 2 in 5 which is a 1 +2.5.  Demachy used a 1 + 2
(2 in 4).  So there you have it--a range of 1 + 3.5 to 1 +
2. Weight in grams to ml water.  
----- Original Message -----
From: Edward Draper <ercdraper@gmail.com>
To: alt-photo-process-l@usask.ca
Subject: Standard strength gum
Date: Tue, 06 Oct 2009 20:44:19 +0100

>Hi guys
>I've managed to get myself addicted to gum printing - I use
>powdered gum (from Silverprint here in the UK)
>And I mix it straight into my pigments - I get a lovely mix
>that is wonderfully variable and leaves beautiful brush
>strokes across the page
>I love the effect - but it is very variable and uses up a
>lot of paper in wasted almost-right prints
>I've been playing around with premix the gum with water
>I've just tried 5g in 100ml
>I see in the latest email trail the following:
>"5 ml of gum (I assume standard strength)"
>What is "standard strength gum"?