Gore-Grunta Fur vs Dark Brown

How close are they?

ΔE 34.4, loose: different enough that you should pick on purpose. Dark Brown is noticeably darker, much more muted than Gore-Grunta Fur.

Can I use Dark Brown instead of Gore-Grunta Fur?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 34). Dark Brown is noticeably darker, much more muted than Gore-Grunta Fur.

Can I use Gore-Grunta Fur instead of Dark Brown?

The same difference applies the other way round: Gore-Grunta Fur is noticeably lighter, much 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.