Digital BW, The Print

John,

The normal simple meaning of the terms is that a dye ink is a solution of 
molecules that possess color, while a pigment ink is a suspension of large 
aggregates of insoluble molecules that possess color.

But these terms were invented by humans a long time ago, and we now have 
colored chemicals that don't fall cleanly into either of these categories. 
As with most terminology and nomenclature, the terms/names/categories are 
not absolute, but have to be changed as our knowledge increases.

With the Ultrachromes, Epson also coated the pigment aggregates with resin, 
and with the new Higloss Ultrachromes they have apparently changed the resin 
to make the particles more glossy.

Bob Frost.

----- Original Message ----- 
From: "john dean" <deanwork2003@...>





My interpretation of these terms was that they distinguish the size of the 
"colorant"
molecules which in "dyes" are smaller and more fluid and break down more 
easily when
exposed to uv and blue radiation, while "pigments", larger more stable 
molecules, have a
much tighter bond.