ΔE 6.8, close: similar, with a visible difference side by side. Transparent Brown is a little darker than Gorthor Brown. They are different kinds of paint: Citadel Gorthor Brown is an opaque base/layer paint and Pro Acryl Transparent Brown 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 Brown is a little darker than Gorthor Brown. They are different kinds of paint.
The same difference applies the other way round: Gorthor Brown 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 Gorthor Brown on the colour wheel See Transparent Brown on the colour wheel
All matches: Gorthor Brown equivalents · Transparent Brown equivalents