Royal Cloak vs Aquamarine

How close are they?

ΔE 8.7, close: similar, with a visible difference side by side. Aquamarine is a little lighter, more saturated than Royal Cloak.

Can I use Aquamarine instead of Royal Cloak?

Usually, if you are not matching paint already on the model. Close match (ΔE 9). Aquamarine is a little lighter, more saturated than Royal Cloak.

Can I use Royal Cloak instead of Aquamarine?

The same difference applies the other way round: Royal Cloak is a little darker, 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.