Digital BW, The Print

I've posted a second graph of paper Lab B fade test results from Aardenburg Imaging.  

See http://www.paulroark.com/BW-Info/OBA-Comparison-2.jpg

In this one I've expanded the papers, which now include Epson Premium Luster, Red River UltraPro Glossy, Red River Polar Matte, Epson Premium Presentation Matte, Hahnemuhle Photo Rage, and Red River Aurora Natural.

Previously Mark noted that the OBAs that were protected by the RC paper barrier would oxidize more slowly.  As such, it makes sense that matte paper OBAs would be more exposed and oxidize faster.  See the graph lines for Red River Polar Matte and Epson Premium Presentation Matte.  They do seem to be oxidizing and fading faster, causing the papers to have increasing Lab B values (getting relatively more yellow) faster than, particularly, the Epson Premium Luster.

One interesting result is the similarity in the Lab B changes for the Epson Premium Presentation Matte and Red River Polar Matte.  It looks like the main difference may be that the underlying Red River paper has a lower (more neutral) Lab B.  

Note also that the H. Photo Rag seems to have very little OBAs in it and a paper base that is rather bright by nature.  It and the Red River Natural are not much different. 

(Note that the initial reads with a number of these papers may be higher due to some artifact of the testing.)

Thanks to Mark and his testing at Aardenburg Imaging -- http://www.aardenburg-imaging.com/ -- we have much more information available to us to understand and compare our materials. 

Paul
www.PaulRoark.com