This invention generally relates to methods and apparatus for driving passive matrix displays, in particular OLED (Organic Light Emitting Diode) displays.A method of driving a passive matrix electroluminescent display, the display having a plurality of rows and columns of emissive elements addressed by respective row and column electrodes, the method comprising: addressing said row electrodes, one at a time; and driving a set of said column electrodes while addressing each said row electrode; wherein said column electrode driving comprises driving said column electrodes to determine ratios of column drive signals to one another for said set of column electrodes; and wherein the method further comprises controlling an overall drive for said set of column electrodes to control a drive to said emissive elements in each said addressed row.