Permanganic reagents, developed for revealing semicrystalline morphology in olefin polymers under the electron microscope, have been modified by changing the water content to give the best resolution of detail in different polyethylene specimens. An optimum reagent is chosen to characterize a special feature of polyethylene spherulites, namely the S-profile of dominant lamellae seen as growing towards the observer. This reagent consists of 1% weight of potassium permanganate in a mixture of 10 volumes concentrated sulphuric acid, 4 volumes of 85% orthophosphoric acid, and 1 volume of water. This study is set in the historical context of banded spherulite studies.