2018-02-01 by richard@...
Oz said it best. Based on the a* and b* measurements the paper base is pretty warm, and you are trying to neutralize it with a lot of magenta/cyan. It works well enough in they highlights and midtones, but as the gray inks get darker you are getting back to the warmth of the gray/black inks combined with the warmth of the paper base. Based on our off-thread conversations about wanting a more neutral tone you might want to use a different paper with less of a warm base.
Hope that helps,
Richard Boutwell
http://www.richardboutwell.com/