ΔE 8.7, close: similar, with a visible difference side by side. Phthalo Green (Blue Shade) is a little darker, more muted, cooler than Potion Green. They are different kinds of paint: Army Painter Potion Green is an opaque base/layer paint and Golden Phthalo Green (Blue Shade) is an ink, glaze or transparent paint, so they won’t behave the same on the model even where the colour is close.
Usually, if you are not matching paint already on the model. Close match (ΔE 9). Phthalo Green (Blue Shade) is a little darker, more muted, cooler than Potion Green. They are different kinds of paint.
The same difference applies the other way round: Potion Green is a little lighter, more saturated, 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 Potion Green on the colour wheel See Phthalo Green (Blue Shade) on the colour wheel
All matches: Potion Green equivalents · Phthalo Green (Blue Shade) equivalents