Kantor Blue vs Violet

How close are they?

ΔE 19.8, loose: different enough that you should pick on purpose. Violet is much more muted, warmer than Kantor Blue.

Can I use Violet instead of Kantor Blue?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 20). Violet is much more muted, warmer than Kantor Blue.

Can I use Kantor Blue instead of Violet?

The same difference applies the other way round: Kantor Blue is much 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.