I'm trying to work out why the Omega D carriers (e.g. D2, D5, etc.) are usually white on top, black on bottom. Most other enlargers seem to use black for both the top and bottom halves and I was trying to work out if this was for a reason (e.g. reflecting light back up into the condensers to somehow make it more even?).

Asking because I made 3D printed negative carriers for various enlargers and am pondering switching to just black for the Omega ones, since all the other carriers I make are black on both halves (e.g. Beseler 67, 45, Zone VI all seem to use black carriers). But if this was for some design reason, I wouldn't want to compromise the performance, though I kinda don't think in practice it would make much of a difference?