Aquamarine vs Hazardous Smog

How close are they?

ΔE 9.7, close: similar, with a visible difference side by side. Hazardous Smog is more saturated, warmer than Aquamarine.

Can I use Hazardous Smog instead of Aquamarine?

Usually, if you are not matching paint already on the model. Close match (ΔE 10). Hazardous Smog is more saturated, warmer than Aquamarine.

Can I use Aquamarine instead of Hazardous Smog?

The same difference applies the other way round: Aquamarine is more muted, 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.