Psychedelic Purple vs Rust

How close are they?

ΔE 58.6, loose: different enough that you should pick on purpose. Rust is a little lighter, much more muted, warmer than Psychedelic Purple.

Can I use Rust instead of Psychedelic Purple?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 59). Rust is a little lighter, much more muted, warmer than Psychedelic Purple.

Can I use Psychedelic Purple instead of Rust?

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