Pistachio vs Poisonous Cloud

How close are they?

ΔE 8.1, close: similar, with a visible difference side by side. Poisonous Cloud is a little lighter than Pistachio.

Can I use Poisonous Cloud instead of Pistachio?

Usually, if you are not matching paint already on the model. Close match (ΔE 8). Poisonous Cloud is a little lighter than Pistachio.

Can I use Pistachio instead of Poisonous Cloud?

The same difference applies the other way round: Pistachio is a little darker.

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.