Blue Violet vs Kakophoni Purple

How close are they?

ΔE 21.7, loose: different enough that you should pick on purpose. Kakophoni Purple is noticeably darker, more muted, warmer than Blue Violet.

Can I use Kakophoni Purple instead of Blue Violet?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 22). Kakophoni Purple is noticeably darker, more muted, warmer than Blue Violet.

Can I use Blue Violet instead of Kakophoni Purple?

The same difference applies the other way round: Blue Violet is noticeably lighter, more saturated, 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.