Leviathan Blue vs Wagram Blue

How close are they?

ΔE 17.5, loose: different enough that you should pick on purpose. Wagram Blue is noticeably darker, more muted, warmer than Leviathan Blue.

Can I use Wagram Blue instead of Leviathan Blue?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). Wagram Blue is noticeably darker, more muted, warmer than Leviathan Blue.

Can I use Leviathan Blue instead of Wagram Blue?

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