Fluor Yellow vs Bile

How close are they?

ΔE 32.5, loose: different enough that you should pick on purpose. Bile is noticeably darker, more saturated, cooler than Fluor Yellow.

Can I use Bile instead of Fluor Yellow?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 33). Bile is noticeably darker, more saturated, cooler than Fluor Yellow.

Can I use Fluor Yellow instead of Bile?

The same difference applies the other way round: Fluor Yellow is noticeably lighter, 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.