Earth Brown vs Knight-Questor Flesh

How close are they?

ΔE 8.9, close: similar, with a visible difference side by side. Knight-Questor Flesh is a little darker, more muted than Earth Brown.

Can I use Knight-Questor Flesh instead of Earth Brown?

Usually, if you are not matching paint already on the model. Close match (ΔE 9). Knight-Questor Flesh is a little darker, more muted than Earth Brown.

Can I use Earth Brown instead of Knight-Questor Flesh?

The same difference applies the other way round: Earth Brown is a little lighter, more saturated.

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.