US Patent 7738139 Inking on photographs

Methods of selecting a color for an electronic ink are disclosed. A portion of a photograph may be analyzed to determine a representative color value, which may be an average color value for the portion. Depending on the photograph, more than one representative color value may be determined. A color or colors, that may include gradients in brightness or saturation levels, which will be visible on the representative color value or values, may then be determined. A color of the electronic ink is then set to the appropriate color or colors so that when a user inks on a photograph, the ink is visible.