This test was on four brands of raw polymer clay using four brands of stamp pad ink. The goal was to see which ones I could form into shapes without smearing the ink. I dabbed the ink on with my gloved finger, waited until they looked dry and tried to smear them.
My conclusion is that StazOn is the most reliable for drying quickly, bonding to the clay and not smearing. However, it doesn’t have the nice color selection that the other three brands do and it has a fairly strong chemical odor.
ColorBox, VersaMagic and Archival Ink will dry in time. Drying can be accelerated by carefully blotting the stamped image with a piece of paper, though this decreases the intensity of the color. Baking will dry them, too.
I previously tested Stampabilities Ink Pad Pigment. The ink was still wet days later, so there must be a chemical reaction that prevents that ink from drying on raw clay.
What surprised me in this test was how Archival Ink’s hydrangea color changed from violet to teal. On the folded paper at the top are what the colors should look like. The teal-colored blobs on the far left of each piece of raw polymer clay are what hydrangea Archival Ink changed into.
I don’t have all the Archival Ink colors, but I tested the following colors to see if they had a similar color shift: Watering Can, Coffee, Tree Branch, Orange Blossom, Violet, Hydrangea and Blue Violet. The sheet of paper to the right shows what they’re supposed to look like. (There’s very little difference in color between Hydrangea and Blue Violet.)
Shortly after applying, the Hydrangea and Blue Violet inks start to shift color. (See photo below.) This is really obvious on Fimo. Tree Branch starts to turn greenish-yellow. Coffee changes slightly. Watering Can, Orange Blossom and Violet remain stable.
After baking (see photo below), there’s even more color shift. The white Fimo and Kato clays have also turned a bit yellow, although they were tented with aluminum foil.
That stamp pad ink works at all on raw clay is rather a miracle, so be sure to test your own inks and colors beforehand to avoid unwelcome surprises.
P.S. I bought all these products myself and received nothing from the manufacturers.