No, no its not, "handicap".
The rainbow is more like lines of color moving by, I believe he wants it to cycle through different colors in the paint set.
I.e its red then its blue then its green, basically fading to each color.
The funky shirt IS NOT the rainbow FX put into a shirt, because if it was it would look like a rainbowed brick, lines moving by in colorful arrays rather than fading from solid colors. I question whether or not you people have used the funky shirt or the rainbow FX.