Warm Yellow vs Parasite Brown

How close are they?

ΔE 9.2, close: similar, with a visible difference side by side. Parasite Brown is a little darker, more saturated than Warm Yellow.

Can I use Parasite Brown instead of Warm Yellow?

Usually, if you are not matching paint already on the model. Close match (ΔE 9). Parasite Brown is a little darker, more saturated than Warm Yellow.

Can I use Warm Yellow instead of Parasite Brown?

The same difference applies the other way round: Warm Yellow is a little lighter, 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.