Grey-Blue 1920s-1930s vs Desert Olive Green

How close are they?

ΔE 11.2, fair: the same colour family, but not a straight swap. Desert Olive Green is a little darker, warmer than Grey-Blue 1920s-1930s.

Can I use Desert Olive Green instead of Grey-Blue 1920s-1930s?

Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Desert Olive Green is a little darker, warmer than Grey-Blue 1920s-1930s.

Can I use Grey-Blue 1920s-1930s instead of Desert Olive Green?

The same difference applies the other way round: Grey-Blue 1920s-1930s is a little lighter, cooler.

ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.