ΔE 13.0, fair: the same colour family, but not a straight swap. Gold Brown is a little lighter, more saturated, cooler than Iridescent Gold Deep (Fine). They are different kinds of paint: Golden Iridescent Gold Deep (Fine) is a pearl paint and Vallejo Gold Brown is a metallic, so they won’t behave the same on the model even where the colour is close.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). Gold Brown is a little lighter, more saturated, cooler than Iridescent Gold Deep (Fine). They are different kinds of paint.
The same difference applies the other way round: Iridescent Gold Deep (Fine) is a little darker, more muted, 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.
See Iridescent Gold Deep (Fine) on the colour wheel See Gold Brown on the colour wheel
All matches: Iridescent Gold Deep (Fine) equivalents · Gold Brown equivalents