Evil Forest vs Old Gold

How close are they?

ΔE 30.5, loose: different enough that you should pick on purpose. Old Gold is much more muted, warmer than Evil Forest.

Can I use Old Gold instead of Evil Forest?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 31). Old Gold is much more muted, warmer than Evil Forest.

Can I use Evil Forest instead of Old Gold?

The same difference applies the other way round: Evil Forest is much 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.