Octopus Purple vs Chaotic Red

How close are they?

ΔE 16.3, loose: different enough that you should pick on purpose. Chaotic Red is more muted, warmer than Octopus Purple.

Can I use Chaotic Red instead of Octopus Purple?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Chaotic Red is more muted, warmer than Octopus Purple.

Can I use Octopus Purple instead of Chaotic Red?

The same difference applies the other way round: Octopus Purple is more saturated, cooler.

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.