Nickel Azo Yellow vs Desert Yellow

How close are they?

ΔE 8.2, close: similar, with a visible difference side by side. Desert Yellow is more saturated than Nickel Azo Yellow.

Can I use Desert Yellow instead of Nickel Azo Yellow?

Usually, if you are not matching paint already on the model. Close match (ΔE 8). Desert Yellow is more saturated than Nickel Azo Yellow.

Can I use Nickel Azo Yellow instead of Desert Yellow?

The same difference applies the other way round: Nickel Azo Yellow is 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.