Paint. I should probably have gone for a darker grey. Oh well, I have another Buff and three more Bone's in the package if it eve starts bothering me too much.
I still can't get enough of the B-52 looking comparatively small and dainty.
On a less sane note, here's someone building Modelsvit's 1/72 Mriya:
https://www.britmodeller.com/forums/index.php?/topic/235075109-modelsvit-172-antonov-225-mriya/