Re: Powdered pigments?
On Fri, 13 Apr 2007, Christina Z. Anderson wrote:
....I have never had a problem with a tube pigment and I've used about 8 different brands.Chris, I'd bet you've only used "artists colors" of known brands & good quality. In the olden days (after we split rails & walked barefoot through the snow to school), we used to find all sorts of hassles with tube paint, though mostly with cheap "sets" students bought somewhere at a bargain... Then again the cheapest set, a japanese product called (as I recall) ninji was excellent, printed beautifully & cost about $4 for a set of small tubes with 10 or 12 colors (tho I can't speak for the archivality).
Then again, most of the colors weren't usable for gum (too pale, and/or too little pigment) so in effect you were paying much more for the 5 or 6 colors you did
The other thing that can be a killer is dispersal agents.... some mixes for whatever purpose (including pure pigments in some kind of emulsion maybe not sold any more but maybe still by an east side NYC company) have a dispersal agent which disperses the pigment so totally into the paper it won't clear.
The other hazard is cheap ("student") paints with so much filler (aluminum hydroxide?) it's impossible to get a strong tone without making the mix so thick it flakes off. These will work for watercolor, because you just add a bit of water & can always layer on another wash. So they're not thinned much at all. In gum printing, of course, there's at least equal water/gum/dichromate added, which weakens the color.