Permanent Orange vs Hot Orange

How close are they?

ΔE 17.6, loose: different enough that you should pick on purpose. Hot Orange is a little darker, more muted, cooler than Permanent Orange.

Can I use Hot Orange instead of Permanent Orange?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 18). Hot Orange is a little darker, more muted, cooler than Permanent Orange.

Can I use Permanent Orange instead of Hot Orange?

The same difference applies the other way round: Permanent Orange is a little lighter, more saturated, 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.