So in my September Favorites post I mentioned that I had really been enjoying my MAC Paint Pot. It works as a base to help your eyeshadow stay on throughout the day, keep it from creasing, and it really intensifies the color. Below is a picture I just took. I have a swatch of just the Paint Pot in Rubenesque (1.) then I used three different eye shadow colors to swatch with and without the Paint Pot underneath.
1. Paint Pot by itself. You can see it's a really gorgeous pink/gold iridescent color. And it can definitely be worn by itself.
2., 4., and 6. Are three different colors that are put on top of the Paint Pot.
3., 5., and 7. Same colors but without being put over a Paint Pot
If you look at the picture and do a color to color comparison (i.e. compare 2. and 3.) you will see just how much the Paint Pot works to really intensify the color of the shadow. It makes the color more vibrant and more true to what you are actually seeing in the shadow's pan.
I image that different colored Paint Pots will intensify the colors differently. Black or matte neutral would have a totally different effect; however, it would still work to make the colors more vibrant in one way or another.
If you are interested in a Paint Pot, I would definitely encourage you to go to your closest MAC counter and talk with someone or play with the Paint Pots yourself. It's fun.