Hello,
I have used Photo Rag Pearl and Photo Rag Baryta during my linearization test made using an Epson R3000,
what I could tell you is that in nine months of full specific B&W research/development and test
for each paper (including the matte ones) I have always measured higher dmax, better neutrality and better linearity in ABW mode vs the color mode, always.
For this reason what you have observed should not be considered normal in my opinion.
Regarding the "impression" of bluish grays on warm papers I can confirm you that a truly neutral gray ramp may absolutely appear a little bit "cool" in the midtones/highlight transition up the not inked paper white color.
To have the objective confirmation if this could be an illusion or not the only way is to print a gray target strip
(18 or 21 patches are more than enough) in both the modes and measure it with a spectrometer.
Looking to the graph I usually make from these measurement any color cast or non linearity will be easily recognizable.
In this way I have recently discovered a bug in the Argyll "chartread" exe
as described in these threads:
http://www.luminous-landscape.com/forum/index.php?topic=82133.0http://www.luminous-landscape.com/forum/index.php?topic=82171.0,
The bug is affecting the ColorMunki readings in strip mode
and resulted in a not neutral black point inside the final paper icc (Photo Rag Baryta in this case).
Note that this bug is still currently present in Argyll version 1.5.0 and 1.6.0 (but not in 1.4.0)
and will hopefully be fixed soon in a new Argyll release
(I have already tested some working beta fix kindly provided to me from Graeme Gill for this purpose).
Back to the topic,
Just to see what I mean,
in attachment you can find 3 graphs of a 18 step wedge gray scale,
one was related to the canned Hahnemuehle ICC for Photo Rag Baryta 315,
one was related to a custom Argyll 1.6.0 ICC made of 840 patches (including 64 grays) for the same paper
the latest was related to ABW mode (neutral dark settings) still using the same paper.
- As visible the canned ICC is the less linear but is still no slouch from neutrality point of view
- The Argyll ICC one is more linear and really neutral from L* 30 up, confirming that Argyll is very capable system,
but is flawed from the mentioned measurement error producing an evident cast starting from L* 30 toward black (which is very purply).
- The ABW is the most linear and neutral of the three and showed a stronger black (L*=3.2 instead of 4.7 of the two ICC).
This is useful to show that, if you have a "real" gray cast somewhere, you will easily discover it in this way.
Any comment is welcome.
Ciao.
Andrea