Ultramarines Blue vs Blue

How close are they?

ΔE 17.3, loose: different enough that you should pick on purpose. Blue is noticeably lighter, more saturated than Ultramarines Blue.

✓ Herrick Games paint comparison chart lists these two as equivalents.

Can I use Blue instead of Ultramarines Blue?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). Blue is noticeably lighter, more saturated than Ultramarines Blue.

Can I use Ultramarines Blue instead of Blue?

The same difference applies the other way round: Ultramarines Blue is noticeably darker, 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.