Dirty Red vs Flat Red

How close are they?

ΔE 12.1, fair: the same colour family, but not a straight swap. Flat Red is a little lighter, cooler than Dirty Red.

Can I use Flat Red instead of Dirty Red?

Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Flat Red is a little lighter, cooler than Dirty Red.

Can I use Dirty Red instead of Flat Red?

The same difference applies the other way round: Dirty Red is a little darker, warmer.

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.