Red Queen vs Ruby Red

How close are they?

ΔE 21.2, loose: different enough that you should pick on purpose. Ruby Red is a little lighter, more muted, cooler than Red Queen.

Can I use Ruby Red instead of Red Queen?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 21). Ruby Red is a little lighter, more muted, cooler than Red Queen.

Can I use Red Queen instead of Ruby Red?

The same difference applies the other way round: Red Queen is a little darker, more saturated, 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.