Fanatic Orange vs Gold Yellow

How close are they?

ΔE 22.6, loose: different enough that you should pick on purpose. Gold Yellow is a little lighter, more saturated, warmer than Fanatic Orange.

Can I use Gold Yellow instead of Fanatic Orange?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 23). Gold Yellow is a little lighter, more saturated, warmer than Fanatic Orange.

Can I use Fanatic Orange instead of Gold Yellow?

The same difference applies the other way round: Fanatic Orange is a little darker, more muted, 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.