1. A digital watermark embedding method comprising: obtaining data associated with a spot color S a , the spot color S a comprising a component of a color design; using one or more configured processors, determining a screen S s of the spot color S a ; selecting a substitute spot color candidate S b1 by: i) evaluating color distance or color error between the substitute spot color candidate S b1 and the screen S s , and ii) evaluating brightness of the substitute spot color candidate S b1 and the screen S s ; using one or more configured processors, determining a Cyan (C), Magenta (M) and Yellow (Y) process color tint that when combined with the substitute spot color candidate S b1 approximates the spot color S a ; transforming a determined CMY process color tint with a digital watermark signal to embed the digital watermark signal in the CMY process color tint, said transforming yielding a watermarked CMY process color tint; and combining the watermarked CMY process color tint and the substitute spot color candidate S b1 , said combining yielding a digital watermarked substitute spot color.