Sigvald Burgundy vs Demon Brown

How close are they?

ΔE 18.8, loose: different enough that you should pick on purpose. Demon Brown is more muted, warmer than Sigvald Burgundy.

Can I use Demon Brown instead of Sigvald Burgundy?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 19). Demon Brown is more muted, warmer than Sigvald Burgundy.

Can I use Sigvald Burgundy instead of Demon Brown?

The same difference applies the other way round: Sigvald Burgundy is more saturated, cooler.

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.