Olive Drab vs Bright Green

How close are they?

ΔE 7.2, close: similar, with a visible difference side by side. Bright Green is more saturated, cooler than Olive Drab.

Can I use Bright Green instead of Olive Drab?

Usually, if you are not matching paint already on the model. Close match (ΔE 7). Bright Green is more saturated, cooler than Olive Drab.

Can I use Olive Drab instead of Bright Green?

The same difference applies the other way round: Olive Drab is more muted, warmer.

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.