True Copper vs Metallic Red

How close are they?

ΔE 30.0, loose: different enough that you should pick on purpose. Metallic Red is a little darker, much more saturated, cooler than True Copper.

Can I use Metallic Red instead of True Copper?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 30). Metallic Red is a little darker, much more saturated, cooler than True Copper.

Can I use True Copper instead of Metallic Red?

The same difference applies the other way round: True Copper is a little lighter, much more muted, warmer.

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.