Back when TUAW posted a review of Paper by FiftyThree for iPad (free, with in-app purchases for brushes and other features), one of the complaints I had was that the app worked with a limited palette of 9 colors and didn't provide a way for artists to mix their own virtual paints. A new upgrade to Paper available today provides a color mixing capability and other new features as well.
The new features in version 1.2.1 of Paper by FiftyThree include the Mixer, a way to create your own custom palettes. The Mixer, like many features available in the app,
