A low frequency value for a pixel value is adjusted by a desired gain. A first high frequency value for the pixel value is calculated. A second high frequency value is generated for the first high frequency value. The second high frequency value is the first high frequency value adjusted by a factor. The factor is resolved as a function of the first high frequency value and the desired gain. A modified value for the pixel value is outputted, where the modified value is the adjusted low frequency value augmented by the second high frequency value.