Gotta disagree with my friend Ctein there. And I think I have done at least as much testing relative
to this subject as he has. But one does not need a full range of multicontrast filters. All you need is
tricolor blue and green, provided you have a sufficiently strong light source. Otherwise, actual colorheads for popular 4x5 enlargers are selling for peanuts right now, even entire enlargers equipped with them. That's all you need.