Satchel Brown vs Seraph Red

How close are they?

ΔE 18.4, loose: different enough that you should pick on purpose. Seraph Red is a little darker, much more saturated, cooler than Satchel Brown.

Can I use Seraph Red instead of Satchel Brown?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 18). Seraph Red is a little darker, much more saturated, cooler than Satchel Brown.

Can I use Satchel Brown instead of Seraph Red?

The same difference applies the other way round: Satchel Brown is a little lighter, much more muted, 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.