Broodmother Purple vs Phthalo Blue RS

How close are they?

ΔE 13.5, fair: the same colour family, but not a straight swap. Phthalo Blue RS is a little lighter, much more saturated, cooler than Broodmother Purple.

Can I use Phthalo Blue RS instead of Broodmother Purple?

Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Phthalo Blue RS is a little lighter, much more saturated, cooler than Broodmother Purple.

Can I use Broodmother Purple instead of Phthalo Blue RS?

The same difference applies the other way round: Broodmother Purple is a little darker, much more muted, 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.