Stationary phases are characterised in a multilinear retention model by retention data of a set of selected prototypical substances. Prototypical stationary phases confirm the application of prototypical substances in the retention model. For comparison, 27 stationary phases are characterized with solute descriptors of the solvation model. New adjusted substance factors are calculated for 33 selected compounds for a new characterization of GC stationary phases in the extended retention model with retention values, calculated from retention indices and b-values of the n-alkane equation. Substance dipolarityD N-factors are separated from πN, the adjusted dipolarity-polarisability. New substance factors give satisfying correlation results and new explanatory factors as phase descriptors for 27 stationary phases.