Castellan Green vs Moss Green

How close are they?

ΔE 9.8, close: similar, with a visible difference side by side. Moss Green is a little darker, more muted, warmer than Castellan Green.

Can I use Moss Green instead of Castellan Green?

Usually, if you are not matching paint already on the model. Close match (ΔE 10). Moss Green is a little darker, more muted, warmer than Castellan Green.

Can I use Castellan Green instead of Moss Green?

The same difference applies the other way round: Castellan Green is a little lighter, more saturated, cooler.

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.