From the developer:
""Helps you paint oil paintings on canvas from digital images from a scanner, digital camera, or the web. You load in a digital image, crop it to fit your canvas, and adjust coloration to suit your tastes. OPA applies a grid to the image to help you more accurately sketch on your canvas. It then displays an analysis of the image showing what paints would be useful for the painting's base coat, and the image's color space so you know if you need different paints. The analysis and grid-overlaid image can be displayed on your monitor while you paint, or printed on a color printer.""