Leviathan Blue vs Orchid Light

How close are they?

ΔE 20.5, loose: different enough that you should pick on purpose. Orchid Light is noticeably lighter, more muted, warmer than Leviathan Blue.

Can I use Orchid Light instead of Leviathan Blue?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 21). Orchid Light is noticeably lighter, more muted, warmer than Leviathan Blue.

Can I use Leviathan Blue instead of Orchid Light?

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