Uniform Grey vs Graphite Gray

How close are they?

ΔE 20.3, loose: different enough that you should pick on purpose. Graphite Gray is noticeably darker, more muted than Uniform Grey.

Can I use Graphite Gray instead of Uniform Grey?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 20). Graphite Gray is noticeably darker, more muted than Uniform Grey.

Can I use Uniform Grey instead of Graphite Gray?

The same difference applies the other way round: Uniform Grey is noticeably 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.