Bright Gold vs Elven Gold

How close are they?

ΔE 20.8, loose: different enough that you should pick on purpose. Elven Gold is a little darker, much more muted than Bright Gold.

Can I use Elven Gold instead of Bright Gold?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 21). Elven Gold is a little darker, much more muted than Bright Gold.

Can I use Bright Gold instead of Elven Gold?

The same difference applies the other way round: Bright Gold is a little 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.