I like the idea of a black with a red or aqua tint. I'm just having a problem picturing it.
By the way, on the topic of black v. blue in professional settings, I had a discussion once with my "superior" and was told that black was professional. Then a co-worker (very intelligent and experienced person) that one of the points of using non-black inks was to instantly tell between copies and originals. When I brought that up, the problem with blue ink went away. I've even used Visconti turquoise on official documents!
By the way, on the topic of black v. blue in professional settings, I had a discussion once with my "superior" and was told that black was professional. Then a co-worker (very intelligent and experienced person) that one of the points of using non-black inks was to instantly tell between copies and originals. When I brought that up, the problem with blue ink went away. I've even used Visconti turquoise on official documents!