Dye ink is used for stamping on lighter colored papers because the color "dyes" the paper and the ink will only show up correctly on lighter colored paper. Dye ink is most commonly used if not embossing since it is so easy to work with and it dries almost instantly.
Pigment ink is a thick, almost paintlike ink. It dries much more slowly than dye ink and may even need to be heat set with a heat gun. Pigment inks may show on darker coloured papers much better than dye, since pigment ink sits on top of the paper surface, rather than soaking into it. Pigment ink is also the ink you use for embossing. When using pigment ink, your stamped images stays wet long enough for embossing powder to stick to it and then allow you to heat it.
If you need any help with your inkpad choices, just ask one of our helpful staff. We have all the inkpads you will ever need in the store!