ΔE 8.5, close: similar, with a visible difference side by side. Fluor Green is a little lighter than Niblet Green. They are different kinds of paint: Citadel Niblet Green is an opaque base/layer paint and Green Stuff World Fluor Green 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 8). Fluor Green is a little lighter than Niblet Green. They are different kinds of paint.
The same difference applies the other way round: Niblet Green is a little darker.
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 Niblet Green on the colour wheel See Fluor Green on the colour wheel
All matches: Niblet Green equivalents · Fluor Green equivalents