Some of them use TiO2 as opacifiers. Some brands cause fog perhaps because
of the nature of the dispersion agents or gum preservatives.
>monochrome I have had good success with the Grumbacher Finest series
>of watercolor, specfifically with Ivory Black, Lamp Black, Raw Sienna,
>and one or two others. The great advantage of watercolor pigments is
>that they disperse wonderfully.
>
>All of my current tissue is made with so-called pure pigments from
>the Color Craft Company of Hartford, CT. These pigments are available in
>4 and 8 oz bottles and are much more economical than the small watercolor
>tubes. I have also obtained numerous pigment samples from companes like
>Dupont, Heubach, Cib-Geigy, etc.
I think Dupont and Ciba are now out of the permanent tricolor set business.
>
>The majority of pigments work fine with carbon printing, but some
>cause staining and fog, others will not disperse well in the gelatin
>solution, while others destroy the bond that holds the pigmented
>gelatin image on the final carrier.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Never heard tell of that one. Do you remember the culprit's name?
I weigh to .1g the amount of
>pigment per 1000ml of solution, and keep good ntoes. If it works,
>great, otherwise chalk it up to experience and move on.
>
>As for dispersions, nothing special. I use 35g of sugar per 1000ml of
>gelatin solution, and 10-15ml of glycerine. I first grind everything
>up very carefully with a pestle and mortar, then mix in a blender at
you mean everything minus the gelatin I presume?
>medium speed for 2-3 minutes. This kicks up a lot of air bubbles and
>you must wait for 2-3 hours to coat, but gives wonderful dispesion.
>A friend of mine tried the blender and swore that it did not work, that
>the bubbles would never go away. But it works fine for me.
Just make very sure that the blade set is never used for food again. I have
never been able to clean them thoroughly
Luis Nadeau
NADEAUL@NBNET.NB.CA
Fredericton, New Brunswick, Canada