Mephiston Red vs Burnt Orange

How close are they?

ΔE 17.0, loose: different enough that you should pick on purpose. Burnt Orange is a little lighter, much more muted, warmer than Mephiston Red.

Can I use Burnt Orange instead of Mephiston Red?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). Burnt Orange is a little lighter, much more muted, warmer than Mephiston Red.

Can I use Mephiston Red instead of Burnt Orange?

The same difference applies the other way round: Mephiston Red 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.