Tinmetal Grey vs Aluminium (Metal.)

How close are they?

ΔE 21.7, loose: different enough that you should pick on purpose. Aluminium (Metal.) is noticeably lighter, more muted than Tinmetal Grey.

Can I use Aluminium (Metal.) instead of Tinmetal Grey?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 22). Aluminium (Metal.) is noticeably lighter, more muted than Tinmetal Grey.

Can I use Tinmetal Grey instead of Aluminium (Metal.)?

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