Re: Gum Printing Techniques

LESMD@aol.com
Thu, 19 Sep 1996 00:30:46 -0400

Marcia,

> how muck gum/pigment is required?

I hope this wasn't a typo because "muck" is exactly what the state of the art
is for the amount of pigment gum and dichromate. The answer is ..... it
depends entirely on the type of paper, amount of size (gelatin or gloy), type
of pigment and type of gum solution used.

The best advice is to start experimenting. First get a good negative with a
density range of about 0.9 to 1.1; one with good shadow and high light
details. I would start with one paper and one gum solution (Photographer's
Formulary is your best bet at this time). Make a series of prints varying
the pigment : dichromate ratio (1:1, 2:1, 1:2 for starters). You'll get tired
of seeing the same image but the education you get from the process is better
than anyone can give you from this list.

Having said that if you insist on a recommendation the use: Fabriano
artistico (sized with gelatin, hardened with glyoxal), Rowney Jet Black
gouache 1gm/5cc of Photographer's Formulary gum arabic; mixed 2:1 with 30%
ammonium dichramate. Depending on the exposure and temperature on the
developing water bath it gives a reasonable one coat gum print.

>Also How much Dichromate solution. I'd probably make
>up 5 or 6 sheets. Can the prepared paper be stored? and how >long before
exposed?

How much pigment/gum/dichromate to make 5-6 sheets of 8x10 paper.... make
more than you think because to little on the brush tends to cause brush marks
to be too obvious. 10 cc of pigment/gum/dichromate per sheet is more than
enough. Use the paper the day that it is made and you won't go wrong.

Happy Gumming,

Larry Shapiro