Skrag Brown vs Burnt Sienna

How close are they?

ΔE 16.5, loose: different enough that you should pick on purpose. Burnt Sienna is a little darker, more muted, cooler than Skrag Brown.

Can I use Burnt Sienna instead of Skrag Brown?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Burnt Sienna is a little darker, more muted, cooler than Skrag Brown.

Can I use Skrag Brown instead of Burnt Sienna?

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