Aspects of the present disclosure relate a head-worn computer with a see-through display wherein computer content is presented to a user wearing the head-worn computer and through which the user sees a surrounding environment, wherein the see-through display generates image light comprised of narrow bandwidths of red, green and blue light and wherein the see-through display further includes a tristimulus notch mirror positioned to reflect the image light towards the user's eye, and wherein the tristimulus notch mirror reflects less than a full width half max of the red image light.