I have no experience with sumi inks, but she should try water colours or tempera
colours, ca. 5-10% of the total weight of the gelatin emulsion. Exact amount
depends on the pigment's covering power. E. g.:
Water, cold 50,0 ml
Sugar 4,0 g
Gelatin 10,0 g
Let gelatin swell for 30 min., then warm up to 45-50 C. In the meantime, prepare
a light-sensitive dispersion of watercolours:
Water 25,0 ml
Wetting agent (Photo-Flo) 0,125 ml
(Schmincke Gouache "Ivory Black)" ca. 8,0 g
(Lukas Tempera Gouache
"Carmine Red") ca. 1,5 g
(Schmincke Gouache
"Caput mortuum violet") ca. 2,0 g
Potassium dichromate sol. 5% 25,0 ml
Combine the two and take about 25 ml to coat a sheet of ca. 8x10". If you want
to store the tissue and need it unsensitized, replace the dichromate solution by
water.
BTW: The tissue we used was from Hanfstaengl - not Hahnemuehle, which is a paper
manufacturer. Good luck,
Klaus Pollmeier