It is a rather difficult task to run a full comparison of all of these different crystals given the sheer amount of crystals available to test (there are probably over 10 different versions of aftermarket AP crystals alone with different AR processing, and even more aftermarket versions of the standard Rolex crystals). What makes it even more difficult is that these crystals are not all uniform, and vary between themselves because of different runs and different AR application procedures even at the same facilities, which have changed over time. The other insurmountable challenge to avoid all subjective bias: one really needs to photograph these crystals on the same watch, in the same geometric/lighting conditions, which is frankly not even 100% possible for even those with professional lighting and photographic equipment. A third requirement, to be perfectly objective, would be the need to photograph all of these crystals in the same situation blind, without knowing which one was being installed, so as not to bias the photographic reproduction in some way.
