Altdorf Guard Blue vs Summersea Blue

How close are they?

ΔE 14.4, fair: the same colour family, but not a straight swap. Summersea Blue is noticeably lighter, more saturated, cooler than Altdorf Guard Blue.

Can I use Summersea Blue instead of Altdorf Guard Blue?

Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Summersea Blue is noticeably lighter, more saturated, cooler than Altdorf Guard Blue.

Can I use Altdorf Guard Blue instead of Summersea Blue?

The same difference applies the other way round: Altdorf Guard Blue is noticeably darker, more muted, 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.