I did the gradient over a white base, putting the colors directly on the sponge and then adding layers on the nail to build the opacity but remain soft. The colors are Lime Crime - Pastelchio and Lime Crime - Once In A Blue Mousse.
This image comes from Sugar Bubbles plate SB 020. I first did the stamping in white but it was practically invisible so I did it again using Sally Hansen Insta-Dri - S-teal a Base.
I actually left the white stamps too for a layered look... and you can't even see it in pictures. I'm really glad I didn't just leave it with the white. Ha!