Night Scales vs Sapphire Blue

How close are they?

ΔE 33.6, loose: different enough that you should pick on purpose. Sapphire Blue is noticeably lighter, much more saturated than Night Scales.

Can I use Sapphire Blue instead of Night Scales?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 34). Sapphire Blue is noticeably lighter, much more saturated than Night Scales.

Can I use Night Scales instead of Sapphire Blue?

The same difference applies the other way round: Night Scales is noticeably 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.