Fiendish Yellow vs Warm Yellow

How close are they?

ΔE 10.4, fair: the same colour family, but not a straight swap. Warm Yellow is a little lighter, more saturated than Fiendish Yellow.

Can I use Warm Yellow instead of Fiendish Yellow?

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

Can I use Fiendish Yellow instead of Warm Yellow?

The same difference applies the other way round: Fiendish Yellow 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.