A method of determining an exposure time for a photosensor based on a desired resolution along a scan direction and a desired resolution in a cross direction may comprise the steps of determining an initial exposure time based on the desired resolution in the cross direction; determining a minimum resolution in the scan direction based on the initial exposure time; comparing the minimum resolution in the scan direction to the desired resolution in the scan direction; and increasing the initial exposure time if the minimum resolution in the scan direction is greater than the desired resolution in the scan direction.