Quick Silver vs Brassy Brass

How close are they?

ΔE 17.8, loose: different enough that you should pick on purpose. Brassy Brass is a little darker, more saturated than Quick Silver.

Can I use Brassy Brass instead of Quick Silver?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 18). Brassy Brass is a little darker, more saturated than Quick Silver.

Can I use Quick Silver instead of Brassy Brass?

The same difference applies the other way round: Quick Silver is a little lighter, more muted.

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.