Flag Red vs Demon Red

How close are they?

ΔE 10.6, fair: the same colour family, but not a straight swap. Demon Red is a little lighter, more saturated than Flag Red.

Can I use Demon Red instead of Flag Red?

Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Demon Red is a little lighter, more saturated than Flag Red.

Can I use Flag Red instead of Demon Red?

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