Red Copper vs Iridescent Copper Light (Fine)

How close are they?

ΔE 11.7, fair: the same colour family, but not a straight swap. Iridescent Copper Light (Fine) is a little lighter, more saturated, warmer than Red Copper. They are different kinds of paint: Army Painter Red Copper is a metallic and Golden Iridescent Copper Light (Fine) is a pearl paint, so they won’t behave the same on the model even where the colour is close.

Can I use Iridescent Copper Light (Fine) instead of Red Copper?

Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Iridescent Copper Light (Fine) is a little lighter, more saturated, warmer than Red Copper. They are different kinds of paint.

Can I use Red Copper instead of Iridescent Copper Light (Fine)?

The same difference applies the other way round: Red Copper is a little darker, more muted, cooler.

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.