Infernal Red vs Sunset Red

How close are they?

ΔE 17.0, loose: different enough that you should pick on purpose. Sunset Red is a little lighter, much more saturated, cooler than Infernal Red.

Can I use Sunset Red instead of Infernal Red?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). Sunset Red is a little lighter, much more saturated, cooler than Infernal Red.

Can I use Infernal Red instead of Sunset Red?

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