Re: Carbon black and gum

In a message dated 02/12/2005 14:51:11 GMT Standard Time,
cactuscowboy@bresnan.net writes:

Carbon black is an excellent choice. I use carbon black (powder pigment)
purchased from Photographer's Formulary, at a ratio of 1g pigment to 100ml
gum. At this ratio, it prints very strong with good clean highlights.

Dave Rose
Powell, Wyoming

> All,
> I want to print very dense black one coat gums. Could anybody give me some
> ideas of what the carbon black to gum ratio can I go to? How much is too
> much pigment? I am just trying to cut down number of my own experiments
> here. Any advice would be appreciated.
> Marek
 .............................................................
Hi Dave and Marek and All, Carbon Black can be animal, vegetable or
mineral based (metal oxide). The popular names for these are Bone or Ivory
(animal), Vine (animal) or Mars(mineral or metal oxide).. Then there is Lamp Black
and Furnace Black which I think are very similar in their origin and its made
by collecting the deposited residue from a flame burning a material. I find
these different ''carbons'' seem to have particles of varying sizes. You can
spend hours trying to mix Lamp black with pure water........the powder just
floats on the surface. Furnace Black, however, mixes readily, but adding a
little ethyl alcohol to the Lamp black will make it missible. I dont think
that gum takes too kindly to being added to alcohol, though......it just
hardens up and ends up like chewing gum. Happily, I am not a gum printer so do not
use gum, altho I do use carbon to make prints.
                       Carbon is not all that simple to work with.
                              John Grocott - photographist
                               SKYPE Number. carbons999
Received on Sat Dec 3 03:38:36 2005