Greedy Gold vs Runic Gold

How close are they?

ΔE 15.4, loose: different enough that you should pick on purpose. Runic Gold is noticeably darker, cooler than Greedy Gold.

Can I use Runic Gold instead of Greedy Gold?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 15). Runic Gold is noticeably darker, cooler than Greedy Gold.

Can I use Greedy Gold instead of Runic Gold?

The same difference applies the other way round: Greedy Gold is noticeably lighter, warmer.

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.