Marduk Yellow vs Bile Green

How close are they?

ΔE 21.2, loose: different enough that you should pick on purpose. Bile Green is a little lighter, more saturated, cooler than Marduk Yellow.

Can I use Bile Green instead of Marduk Yellow?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 21). Bile Green is a little lighter, more saturated, cooler than Marduk Yellow.

Can I use Marduk Yellow instead of Bile Green?

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