It's the look of printed background paper for the Eggplant background on this card thanks to words stamped with bleach. If you've never done that, it won't hurt your stamps. Just pour a little bit of bleach onto a white paper towel that's folded up on a bleach safe surface -- or -- BIG TIP HERE -- I like to use white felt in a plastic stamp box. Use the bleach just like an ink pad. You never know what color the CS will bleach out to -- and it can even vary on the same color CS if it's from a different "batch." I do clean my stamps after using bleach and condition them with the SU Stampin' Mist. Donna Herring -- who's a demonstrator in my 3-2-1 Stamp! group made this great card as her very first swap card. Colors used are Almost Amethyst, Eggplant, Celery and Chocolate Chip.
This is so fun to see the Sellabration sets in action each day. Remember you can get them free until the end of Fenruary. See the link in the right column for details on how.