Desert Yellow vs Bone Khaki

How close are they?

ΔE 19.9, loose: different enough that you should pick on purpose. Bone Khaki is noticeably lighter, much more muted than Desert Yellow.

Can I use Bone Khaki instead of Desert Yellow?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 20). Bone Khaki is noticeably lighter, much more muted than Desert Yellow.

Can I use Desert Yellow instead of Bone Khaki?

The same difference applies the other way round: Desert Yellow is noticeably darker, much more saturated.

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.