Why sawdust?

[Grafist@aol.com]

Hi again,  "A" List Folk,
               My Direct Carbon  Pigment Sawdust Abrasion Print Process.

As there seems to be some interest in the above I feel moved to offer a few 
clues as to the system which I use which exactly follows  the widely 
published info on both the Fresson and Carbondir (Echague) methods of 
development using sawdust in water to remove surplus pigment from the surface 
of the print after  UV exposure has been made through a contact negative onto 
the prepared paper. The parameters used for achieving a well balanced tonal 
print i.e. one which includes a tonal range following the desires of the 
artist/photog are as follows...
1. The strength of the sensitizer.
2. The duration of the  UV exposure.
3. The temperature of the water bath stages.
4. Sawdust abrasion manipulation and control in specifric areas of the print.

All of these stages are variables and especially  the sawdust abrasion stage 
which is the essence of this DC process and marks it out as unique among  
photo image making methods.The published formulae given by Echague is very 
specific regarding water bath temperatures. Another special feature is that 
even after thorough drying of the paper print one may resoak it and continue 
with sawdust manipulation.  Sawdust offers a mechanical way of removing 
pigment from the surface of a print rather similar to the way bromoil ink is 
removed from an inked up matrix with a brush or roller. I have tried using 
both brushes and water jets but nothing beats the well tried and tested 
sawdust. I use pellets of cat litter which are available at Tesco stores in 5 
kg bags. These pellets contain no gum to bind them together so they dissolve 
readily in cold water to form a slurry which can be poured from a jug as 
Echague describes. Varying the height of the jug from the print changes the 
action of the sawdust in removing the pigment.
I SHOULD EMPHASIZE THAT  TO MY KNOWLEDGE MY DC PROCESS IS NEITHER THE FRESSON 
OR CARBONDIR PROCESS.
 I would be pleased to add some further directions if anyone has any 
questions. 
                               Regards
 John Grocott - Photographist and Direct Carbon Printmaker . London(England)