ΔE 14.5, fair: the same colour family, but not a straight swap. Tarnished Brass is a little lighter, much more saturated than Balthasar Gold.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 15). Tarnished Brass is a little lighter, much more saturated than Balthasar Gold.
The same difference applies the other way round: Balthasar Gold is a little darker, much more muted.
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 Balthasar Gold on the colour wheel See Tarnished Brass on the colour wheel
All matches: Balthasar Gold equivalents · Tarnished Brass equivalents