Aqua Alchemy vs Viridian Green Hue

How close are they?

ΔE 16.2, loose: different enough that you should pick on purpose. Viridian Green Hue is noticeably darker, more muted, warmer than Aqua Alchemy.

Can I use Viridian Green Hue instead of Aqua Alchemy?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Viridian Green Hue is noticeably darker, more muted, warmer than Aqua Alchemy.

Can I use Aqua Alchemy instead of Viridian Green Hue?

The same difference applies the other way round: Aqua Alchemy 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.