Does no one hear me?
Paper (reflection print material) cannot go over about 2.2 in density and varies from 1.8 to 2.2 depending on surface quality. Reflection densities in high regions are therefore hard to read.
Also, read up on "goniophotometry". This describes the variation in density of reflection print materials as a function of the angle of measurement or viewing. I have done a lot of work on all of the above.
If you want to talk about densitometry, please leave out reflection!!!!! There does not seem to be enough understanding of this topic.