Evil Sunz Scarlet vs Primary Red

How close are they?

ΔE 6.8, close: similar, with a visible difference side by side. Primary Red is a little lighter than Evil Sunz Scarlet.

Can I use Primary Red instead of Evil Sunz Scarlet?

Usually, if you are not matching paint already on the model. Close match (ΔE 7). Primary Red is a little lighter than Evil Sunz Scarlet.

Can I use Evil Sunz Scarlet instead of Primary Red?

The same difference applies the other way round: Evil Sunz Scarlet is a little darker.

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.