Yellow Shadow vs Deathclaw Brown

How close are they?

ΔE 6.4, close: similar, with a visible difference side by side. Deathclaw Brown is cooler than Yellow Shadow.

Can I use Deathclaw Brown instead of Yellow Shadow?

Usually, if you are not matching paint already on the model. Close match (ΔE 6). Deathclaw Brown is cooler than Yellow Shadow.

Can I use Yellow Shadow instead of Deathclaw Brown?

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