Here is a printable that I made back in 2011 and just updated: Mixed Up Chameleon and A Color of His Own – Be Myself – free printable from OMazing Kids.
This color mixing activity is that the colors take a while to blend. It gives the kids a chance to really study the mixing process and see it happen gradually.
Use with Eric Carle's The Mixed Up Chameleon. Bleeding art tissue paper cut into squares, paint the paper with water and lay the squares in single layers ...