The selection of a reversed-phase liquid chromatographic column with suitable selectivity for a particular separation is difficult if the brand name of the column is not known. A project to develop a chromatographic test procedure to characterize reversed-phase liquid chromatography C18 columns was started earlier and resulted in a fast, simple, repeatable and reproducible test procedure using four column parameters. Here, this procedure is used to evaluate the diversity of columns originating from the same batch as well as from different batches. The determination of one of the parameters, the retention factor of 2,2'-dipyridyl, was improved and a simplified test procedure is proposed.