Akunabo ubuthi, ukumelana nesimo sezulu, ukumelana namakhemikhali, okuzinzile, ukumuncwa kwamanzi aphansi, amelana nama-asidi abuthakathaka nezincibilikisi zemvelo.Ukukhanya okuphezulu, kungavimba ukukhanya kwe-ultraviolet, isicwebezelisi esihle.