I had a weird problem while printing the other day.
A couple of the latest B&W photos I was printing to an ~11x14 size
were coming out with a slight magenta tint on the Epson Enhanced
Matte A3 paper. This despite being fully color managed and making
dozens of seemingly identical, perfectly neutral renderings of the
same file on the same paper in US Letter size. My guess is that that
box of EEM has a slightly off formulation with respect to the EEM
profile supplied for the printer.
Thankfully, the Epson R2400 has the "Advanced B&W" options. I told
Photoshop to let the printer do the color adjustments and then used
the B&W controls in the Epson driver to print the image with a
slightly warm tone.
Two others of the photos in that set have a lot of very deep tones.
The difference between the just printed copy and the fully dried-down
copy a day later is large ...
Printing remains a fussy business, regardless of how sophisticated
the technology. Where the ink hits the paper remains a certain amount
of one-by-one randomness.
Godfrey