Burnt Umber vs Matt Varnish

How close are they?

ΔE 68.5, poor: a clearly different colour, so not a substitute. Matt Varnish is noticeably lighter, much more muted than Burnt Umber.

Can I use Matt Varnish instead of Burnt Umber?

Not as a straight swap; see the closer alternatives below. Poor match (ΔE 69). Matt Varnish is noticeably lighter, much more muted than Burnt Umber.

Can I use Burnt Umber instead of Matt Varnish?

The same difference applies the other way round: Burnt Umber is noticeably darker, much more saturated.

ΔE is the colour difference between our two swatch estimates: under 2 is a perfect match (you’d struggle to tell them apart), under 6 very close, under 10 close, under 15 fair, under 20 loose, under 30 very loose, and 30 or more a poor match. Real paints also differ in finish, coverage and how they thin, so test before you commit.