Dead Red vs Evil Sunz Scarlet

How close are they?

ΔE 16.7, loose: different enough that you should pick on purpose. Evil Sunz Scarlet is noticeably darker, more saturated than Dead Red.

Can I use Evil Sunz Scarlet instead of Dead Red?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). Evil Sunz Scarlet is noticeably darker, more saturated than Dead Red.

Can I use Dead Red instead of Evil Sunz Scarlet?

The same difference applies the other way round: Dead Red is noticeably lighter, more muted.

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.