Doomfire Drab vs Titanium White

How close are they?

ΔE 16.1, loose: different enough that you should pick on purpose. Titanium White is a little lighter, more muted than Doomfire Drab.

Can I use Titanium White instead of Doomfire Drab?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Titanium White is a little lighter, more muted than Doomfire Drab.

Can I use Doomfire Drab instead of Titanium White?

The same difference applies the other way round: Doomfire Drab is a little darker, 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.