Squig Orange vs Phoenix Red

How close are they?

ΔE 8.6, close: similar, with a visible difference side by side. Phoenix Red is a little darker than Squig Orange.

Can I use Phoenix Red instead of Squig Orange?

Usually, if you are not matching paint already on the model. Close match (ΔE 9). Phoenix Red is a little darker than Squig Orange.

Can I use Squig Orange instead of Phoenix Red?

The same difference applies the other way round: Squig Orange is a little lighter.

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.