Radiation Glow vs Naples Yellow Deep

How close are they?

ΔE 9.8, close: similar, with a visible difference side by side. Naples Yellow Deep is more saturated than Radiation Glow.

Can I use Naples Yellow Deep instead of Radiation Glow?

Usually, if you are not matching paint already on the model. Close match (ΔE 10). Naples Yellow Deep is more saturated than Radiation Glow.

Can I use Radiation Glow instead of Naples Yellow Deep?

The same difference applies the other way round: Radiation Glow is 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.