<<  process.  This brings up a different question.  I think I would be more
 > successful using a middle-tone paper and printing up both highlights and
 > shadows.  The problem is:  what colored paper can hold up to
 > multiple-coat gum printing?
 > Any suggestions are welcome.
 > 
 > Robert Revere >>
Some years ago I had a great deal of fun printing just as you describe.  I
used two methods to achieve the grey toned paper I wanted.  The first was to
add acrylic color to my gesso sizing.   The second was to coat a grey coat of
gum bichromate and expose without a neg.  For myself I much preferred using
the colored gesso.  Also after having watched a drawing class at school,  I
printed the shadow coats with a deep red such as Indian Red with a touch of
Black added.   If you print nudes using this technique people will know right
off you're an "artist".  
Bernie
Bernard Boudreau