Gehenna's Gold vs Heirloom Gold

How close are they?

ΔE 17.1, loose: different enough that you should pick on purpose. Heirloom Gold is a little lighter, much more muted than Gehenna's Gold.

Can I use Heirloom Gold instead of Gehenna's Gold?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). Heirloom Gold is a little lighter, much more muted than Gehenna's Gold.

Can I use Gehenna's Gold instead of Heirloom Gold?

The same difference applies the other way round: Gehenna's Gold is a little darker, 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.