ΔE 7.1, close: similar, with a visible difference side by side. Transparent Yellow is a little darker than Phalanx Yellow. They are different kinds of paint: Citadel Phalanx Yellow is an opaque base/layer paint and Green Stuff World Transparent Yellow 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 7). Transparent Yellow is a little darker than Phalanx Yellow. They are different kinds of paint.
The same difference applies the other way round: Phalanx Yellow is a little lighter.
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 Phalanx Yellow on the colour wheel See Transparent Yellow on the colour wheel
All matches: Phalanx Yellow equivalents · Transparent Yellow equivalents