Re: How does the 'crayola color explosion' pen and paper work?

Dear Sue,


There are a group of dyes that change color when they are mixed with 
certain "magic" chemicals. The dyes react with these chemicals, causing 
them to turn a different color or go colorless (turn clear). Our product 
uses these dyes: We start with a sheet of paper that has a pattern of 
colorful swirls printed on it.  We cover the paper with a special black 
coating.  The coating has dyes that lose their color when mixed with 
those magic chemicals.  We then make an ink (and place it in a marker) 
that has some magic chemical in it.  So when you color with the marker on 
the Color Explosion paper, the chemical in the marker mixes with the 
black coating on top of the paper. The color disappears, exposing the 
colorful pattern on the paper underneath...

Colorfully Yours,
Dr. Crayola