Dark Yellow Green vs Olive Green

How close are they?

ΔE 9.1, close: similar, with a visible difference side by side. Olive Green is a little lighter, cooler than Dark Yellow Green.

Can I use Olive Green instead of Dark Yellow Green?

Usually, if you are not matching paint already on the model. Close match (ΔE 9). Olive Green is a little lighter, cooler than Dark Yellow Green.

Can I use Dark Yellow Green instead of Olive Green?

The same difference applies the other way round: Dark Yellow Green is a little darker, 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.