RLM 79 (1942) vs Orange Brown

How close are they?

ΔE 14.8, fair: the same colour family, but not a straight swap. Orange Brown is a little darker, more saturated than RLM 79 (1942).

Can I use Orange Brown instead of RLM 79 (1942)?

Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 15). Orange Brown is a little darker, more saturated than RLM 79 (1942).

Can I use RLM 79 (1942) instead of Orange Brown?

The same difference applies the other way round: RLM 79 (1942) is a little lighter, more muted.

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.