It was suggested [Bala_CIC17] that metamerism could be exploited for watermarking applications by utilizing narrowband LED illuminant spectra for breaking apart metamer colors. It was noticed that, for metameric ink reflectances differing only by the K ink contribution, absolute differences between metamer pairs peaked around a few wavelengths: LEDs with those spectra were then used for displaying the watermarks.Here we investigate the idea of interposing a camera and a display system to make the effects produced more pronounced. We develop an optimization to produce a matrix that best transforms the camera sensors such that color differences between erstwhile metamer pairs are maximized, under the new lights. As well, we consider the problem of optimizing on the lighting itself in addition, leading to even more emphatic breaking apart of metamer pairs and thus more visible watermarks.