Cygor Brown vs Deep Purple

How close are they?

ΔE 25.3, loose: different enough that you should pick on purpose. Deep Purple is a little darker, cooler than Cygor Brown.

Can I use Deep Purple instead of Cygor Brown?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 25). Deep Purple is a little darker, cooler than Cygor Brown.

Can I use Cygor Brown instead of Deep Purple?

The same difference applies the other way round: Cygor Brown is a little lighter, 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.