Digital BW, The Print

Gum prints are made using gum arabic (with watercolor pigment of your 
choice) which is made light sensitve with potassium bi-chromate and 
then hand coated onto gelatin sized watercolor paper (e.g Arches).
  
It is very slow and thus must be exposed to a UV source such as 
sunlight (or a sun-lamp) for about 10 minutes via contact printing.  
Since it is too slow for projection printing, one needs a way to make 
an enlarged neg unless one is  using a large-format camera. They are 
thus "photographic watercolors". 

Digital printing onto transparency  stock is a relatively easy way to 
make the enlarged negs and since the  negative can be damaged when it 
comes into contact with the fresh damp hand coated emulsion - not a 
bad thing to be able to make copies.

In  addition if color seperation negatives are made and the 
appropriate  colors of watercolor pigment are used (e.g red, blue, 
yellow) and the negs are registered - one can make true color photos -
indeed this was  one of the earliest ways of doing so.  

Probably more than you wanted to  know.

The prints can be black and white if black pigment is used and the 
paper is white - just  so you know this isn't OT - but usually a 
monochrome print is made with  a color such as burnt umber - for 
example....Anyway it can be a lot of fun ....Michael vendrell

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Byron Sanford" 
<bmgs@h...> wrote:
>
> --- In DigitalBlackandWhiteThePrint@yahoogroups.com, "pepejaffa"
> <pepejaffa@y...> wrote:
> >
> > I'm hoping to make some gum prints from inkjet negs made using a 
> > rather crappy Lexmark z33 and inkjet transparency sheets from k-
mart 
> > (i.e. low budget).
> > 
> > Would welcome any suggestions, advice...
> > 
> > Pepe
> >
> This sounds interesting. What are you trying to create here? I'm not
> familiar with gum prints.
>