Actually, a great number of reflection densitometers were made specifically for photo papers. Remember, every processing lab that used standard "process control" methods had to do this for both film AND paper. I can assure you that older machines, at least Macbeth and X-rite, did a fine job on photo paper, glossy or otherwise. I think there is just less need for these things, with respect to a regular photographer (as opposed to a lab operator, or researcher, or the like).
Originally Posted by ic-racer