Digital BW, The Print

Jeff,
 
> ... since archival properties get discussed here fairly obsessively...

True, we B&W printers have that tendency.

> I might propose that
> Wilhelm's numbers are perhaps best understood as unitless ...

I agree.  As relative ratings, I think they are valuable information that
will help all of us. 


> I think what Wilhelm provides are (a) testing with a consistent
> methodology resulting in comparable results from test to test, and (b)
> testing in which inconsistent methodology is documented...

Yes, hopefully, and to the extent known.  

What I'm looking at in my highlight fade tests is whether the methodology
gives us relative results that are valid for those highlights that appeared
in my scans to have substantial color ink contest.  Wilhelm appears to use
0.60 and 1.0 starting density patches for testing.  I'm curious if this
misses an important divergence of relative performance in the highlights.

With the Epson Archival inkset, thought by many to be the most archival
desktop inkset, I found that the black reacted in my tests like a hybrid
pigment-dye ink, fading significantly faster than the UC PK and MK.  (The
quad inksets I've made from the Epson Archival inkset have also not
performed as well as those made from UC and MIS pigments.)  One would not
get that impression from the published tests that use only relatively
midtone test points.  

The more information the better.

Paul
www.PaulRoark.com