Thanatos Grey vs USAF Medium Gray

How close are they?

ΔE 17.3, loose: different enough that you should pick on purpose. USAF Medium Gray is a little darker, more muted than Thanatos Grey.

Can I use USAF Medium Gray instead of Thanatos Grey?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). USAF Medium Gray is a little darker, more muted than Thanatos Grey.

Can I use Thanatos Grey instead of USAF Medium Gray?

The same difference applies the other way round: Thanatos Grey is a little lighter, 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.