ΔE 7.2, close: similar, with a visible difference side by side. Pastel Yellow is more muted than Matt Yellow. They are different kinds of paint: AMMO by Mig Matt Yellow is an ink, glaze or transparent paint and Army Painter Pastel Yellow is a one-coat contrast-style 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 7). Pastel Yellow is more muted than Matt Yellow. They are different kinds of paint.
The same difference applies the other way round: Matt Yellow is more saturated.
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 Matt Yellow on the colour wheel See Pastel Yellow on the colour wheel
All matches: Matt Yellow equivalents · Pastel Yellow equivalents