This patent document relates generally to steganography and digital watermarking. One claim recites an apparatus comprising: electronic memory for buffering samples corresponding to imagery; and a programmed processor. The processor is programmed for: analyzing the samples corresponding to the imagery to determine whether a color value comprises color saturation; adjusting the samples to adjust the color saturation into a linear region, the adjusting yielding adjusted samples; encoding the auxiliary information in the adjusted samples, said encoding adapted to an anticipated watermark detection. Of course, other claims and combinations are provided too.