A control system for a display comprising a backlight having a plurality of individually controllable light emitters configured to project light onto a front modulator having a plurality of individually controllable light transmission elements, the control system comprising: an input unit configured to receive image data specifying a desired image at an initial spatial resolution; a downsampler configured to downsample the image data into a plurality of downsample blocks at a downsample spatial resolution lower than the initial spatial resolution and obtain a plurality of values for each downsample block; wherein the image values comprise a peak value and an average value for each downsample block; an image value adjuster configured to receive the image values for the downsample blocks from the downsampler, to reduce the average value for each downsample block which meets adjustment criteria and to provide the reduced average values to a backlight processing pipeline, wherein then backlight processing pipeline is configured to determine driving levels for the light emitters of the backlight based on the reduced average values output from the image value adjuster so that the reduced average values result in a reduction in the power consumption of the correspoding light emitters of the backlight; a lightfield simulator configured to receive backlight driving data about the driving levels and to transform the backlight driving data into a backlight illumination pattern; and, a front modulator processing pipeline configured to receive the image data from the input unit and the backlight illumination pattern from the lightfield simulator and to determine control levels for the light transmission elements of the front modulator; wherein the adjustment criteria are met when the peak value is below an upper watermark and the average value is above a lower watermark, wherein image values and upper and lower watermarks are represented using N bits, where N is a positive integer; wherein the upper watermark has a value of 2 N-1 -1, and the lower watermark has a value of 2 M - 1, where M is a positive integer less than N-1. an input unit configured to receive image data specifying a desired image at an initial spatial resolution; a downsampler configured to downsample the image data into a plurality of downsample blocks at a downsample spatial resolution lower than the initial spatial resolution and obtain a plurality of values for each downsample block; wherein the image values comprise a peak value and an average value for each downsample block; an image value adjuster configured to receive the image values for the downsample blocks from the downsampler, to reduce the average value for each downsample block which meets adjustment criteria and to provide the reduced average values to a backlight processing pipeline, wherein then backlight processing pipeline is configured to determine driving levels for the light emitters of the backlight based on the reduced average values output from the image value adjuster so that the reduced average values result in a reduction in the power consumption of the correspoding light emitters of the backlight; a lightfield simulator configured to receive backlight driving data about the driving levels and to transform the backlight driving data into a backlight illumination pattern; and, a front modulator processing pipeline configured to receive the image data from the input unit and the backlight illumination pattern from the lightfield simulator and to determine control levels for the light transmission elements of the front modulator; wherein the adjustment criteria are met when the peak value is below an upper watermark and the average value is above a lower watermark, wherein image values and upper and lower watermarks are represented using N bits, where N is a positive integer; wherein the upper watermark has a value of 2 N-1 -1, and the lower watermark has a value of 2 M - 1, where M is a positive integer less than N-1.