Sky Blue vs Troglodyte Blue

How close are they?

ΔE 8.7, close: similar, with a visible difference side by side. Troglodyte Blue is more saturated, cooler than Sky Blue.

Can I use Troglodyte Blue instead of Sky Blue?

Usually, if you are not matching paint already on the model. Close match (ΔE 9). Troglodyte Blue is more saturated, cooler than Sky Blue.

Can I use Sky Blue instead of Troglodyte Blue?

The same difference applies the other way round: Sky Blue is more muted, warmer.

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.