I think that would be difficult because of the definition Dr=log(Max reflectance/Min reflectance). So even a hypothetical extreme change from say 100% to 85% would give a difference of 0.07. Conversely, if the min changes from 5% to 10%, you get a change of 0.3
(Actually I thought that Dmax was already defined as the ratio, ie Dmax= dynamic range, but maybe that is non-standard?)
You could quote in Lab values then to get a better representation of the perceptual effect. This has been discussed before on the DPreview forum and Mark McCormick corrected my misunderstanding of the effect then, something I did not forget:
http://www.dpreview.com/forums/thread/3722471>> Ernst, as you probably know, optical density is a very non linear scale when it comes to humanl visual perception. A dmax of 2.5 equals an L* value of 2.8 while a DMax of 2.8 equals an L* value of 1.4. That is an L* difference of 1.4 which is only slightly more than a "just noticeable difference" to the human observer under appropriate viewing conditions. At the other end of the density scale, 0.0 OD equates to a perfectly diffuse white 100% reflecting surface hence L* = 100. 0.3 OD equals an L* value of 76.1. That's a huge perceived difference, i.e "extremely noticeable" to the human observer. What all these numbers boil down to is that choosing a paper with media whtiepoint L*=98 over one like PGPP at 95.0 will give you a delta L* change of 3.0 units which is significantly more noticeable to the human observer than the change from Dmax of 2.5 to 2.8. Moreover, the Dmax measurement of 2.8 is unsustainable. It is achieved only for a very fresh-off-the-printer print. Give the print a few days, and any Dmax above 2.6 will usually settle back down to more typical values. Also, most of the spectrophotometers used for ICC profiling these days, can't read a 2.8 Dmax all that reliably. For both reasons, the Epson claim of highest industry Dmax doesn't impress me much.<<
Edit: To illustrate this, within the Fibre/Baryta Satin/Lustre/Gloss group of inkjet papers the paper white can vary between slightly less than L 94 and almost up to L 99. The Canson Platine is one in the middle of that, L 97.
Met vriendelijke groet, Ernst
http://www.pigment-print.com/spectralplots/spectrumviz_1.htmJanuary 2016 update, 700+ inkjet media white spectral plots