Kantor Blue vs Dark Ultramarine

How close are they?

ΔE 16.2, loose: different enough that you should pick on purpose. Dark Ultramarine is a little lighter, much more saturated than Kantor Blue.

Can I use Dark Ultramarine instead of Kantor Blue?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Dark Ultramarine is a little lighter, much more saturated than Kantor Blue.

Can I use Kantor Blue instead of Dark Ultramarine?

The same difference applies the other way round: Kantor Blue is a little darker, much more muted.

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.