Gold Leaf vs Imperial Gold

How close are they?

ΔE 22.4, loose: different enough that you should pick on purpose. Imperial Gold is much more muted, warmer than Gold Leaf.

Can I use Imperial Gold instead of Gold Leaf?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 22). Imperial Gold is much more muted, warmer than Gold Leaf.

Can I use Gold Leaf instead of Imperial Gold?

The same difference applies the other way round: Gold Leaf 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.