Bright Green vs Sick Green

How close are they?

ΔE 7.8, close: similar, with a visible difference side by side. Sick Green is more saturated than Bright Green.

Can I use Sick Green instead of Bright Green?

Usually, if you are not matching paint already on the model. Close match (ΔE 8). Sick Green is more saturated than Bright Green.

Can I use Bright Green instead of Sick Green?

The same difference applies the other way round: Bright Green 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.