ΔE 13.5, fair: the same colour family, but not a straight swap. Goblin Green is a little lighter, more muted, warmer than Shamrock Green. They are different kinds of paint: Army Painter Shamrock Green is a one-coat contrast-style paint and Vallejo Goblin Green is an opaque base/layer paint, so they won’t behave the same on the model even where the colour is close.
✓ Herrick Games paint comparison chart lists these two as equivalents.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). Goblin Green is a little lighter, more muted, warmer than Shamrock Green. They are different kinds of paint.
The same difference applies the other way round: Shamrock Green is a little darker, more saturated, 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.
See Shamrock Green on the colour wheel See Goblin Green on the colour wheel
All matches: Shamrock Green equivalents · Goblin Green equivalents