ΔE 9.1, close: similar, with a visible difference side by side. Phthalo Green is a little lighter, warmer than Stegadon Scale Green.
Usually, if you are not matching paint already on the model. Close match (ΔE 9). Phthalo Green is a little lighter, warmer than Stegadon Scale Green.
The same difference applies the other way round: Stegadon Scale Green is a little darker, 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 Stegadon Scale Green on the colour wheel See Phthalo Green on the colour wheel
All matches: Stegadon Scale Green equivalents · Phthalo Green equivalents