Arid Earth vs Titan Buff

How close are they?

ΔE 16.1, loose: different enough that you should pick on purpose. Titan Buff is a little darker, much more muted, warmer than Arid Earth.

Can I use Titan Buff instead of Arid Earth?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Titan Buff is a little darker, much more muted, warmer than Arid Earth.

Can I use Arid Earth instead of Titan Buff?

The same difference applies the other way round: Arid Earth is a little lighter, much more saturated, cooler.

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.