A method for a display device comprising a drive circuit, wherein the display device comprises a plurality of pixels operable at a plurality of grey levels in accordance with a respective plurality of analog drive voltages, wherein each pixel is selectively-connectable to the output of any one single grey-level channel of the plurality of single grey-level channels, the drive circuit comprising a plurality of single grey-level channels, wherein each single grey-level channel comprises an input, an output and a signal processor connected between the input and output, wherein each signal processor comprises a digital-to-analog converter, "DAC", and an operational amplifier, "op-amp", having a voltage offset, the method comprising: converting a digital signal received at the input into an analog voltage at the output using each respective signal processor; switchably-receiving the analog voltage of each single grey-level channel of the plurality of single grey-level channels; analysing the analog voltages; and individually compensating for the voltage offset of each op-amp based on the received analog voltage for that grey-level channel, wherein analysing the analog voltages from the switching circuit comprises: individually determining the output response of each single grey-level channel to a plurality of digital inputs; and for each single grey-level channel, determining the digital input required to achieve each analog drive voltage at the output based on the individually-determined output response of that grey-level channel; the method further comprising: selecting the plurality of grey levels based on a predetermined grey level response of the pixels to analog voltage; and determining the plurality of analog drive voltages required by the pixels to achieve the respective selected plurality of grey levels; the method further comprising: assigning a different grey-level to each single grey-level channel and establishing the digital input required by each single grey-level channel to output the required analog voltage for the respectively-assigned grey-level, and changing the assignment of grey-levels between the single grey-level channels during display. converting a digital signal received at the input into an analog voltage at the output using each respective signal processor; switchably-receiving the analog voltage of each single grey-level channel of the plurality of single grey-level channels; analysing the analog voltages; and individually compensating for the voltage offset of each op-amp based on the received analog voltage for that grey-level channel, wherein analysing the analog voltages from the switching circuit comprises: individually determining the output response of each single grey-level channel to a plurality of digital inputs; and for each single grey-level channel, determining the digital input required to achieve each analog drive voltage at the output based on the individually-determined output response of that grey-level channel; individually determining the output response of each single grey-level channel to a plurality of digital inputs; and for each single grey-level channel, determining the digital input required to achieve each analog drive voltage at the output based on the individually-determined output response of that grey-level channel; the method further comprising: selecting the plurality of grey levels based on a predetermined grey level response of the pixels to analog voltage; and determining the plurality of analog drive voltages required by the pixels to achieve the respective selected plurality of grey levels; selecting the plurality of grey levels based on a predetermined grey level response of the pixels to analog voltage; and determining the plurality of analog drive voltages required by the pixels to achieve the respective selected plurality of grey levels; the method further comprising: assigning a different grey-level to each single grey-level channel and establishing the digital input required by each single grey-level channel to output the required analog voltage for the respectively-assigned grey-level, and changing the assignment of grey-levels between the single grey-level channels during display. assigning a different grey-level to each single grey-level channel and establishing the digital input required by each single grey-level channel to output the required analog voltage for the respectively-assigned grey-level, and changing the assignment of grey-levels between the single grey-level channels during display.