Mustard vs Yellow RLM04

How close are they?

ΔE 10.5, fair: the same colour family, but not a straight swap. Yellow RLM04 is a little darker, more saturated than Mustard.

✓ AMMO ATOM user guide chart lists these two as equivalents.

Can I use Yellow RLM04 instead of Mustard?

Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 10). Yellow RLM04 is a little darker, more saturated than Mustard.

Can I use Mustard instead of Yellow RLM04?

The same difference applies the other way round: Mustard 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.