Displays systems and methods for producing a single scaling factor to image data values are disclosed. In one embodiment of a display system uses a post-scaling module. A post-scaling unit for scaling image data values is constructed as a function of many scaling requirements such as backlight illumination from said illumination determination unit, saturation of the image data values and out-of-gamut correction—to produce a single scaling factor. This single scaling factor may be a function of a number of scaling requirements as described herein. Some of these scaling requirements could be selected from a group scaling considerations, such as saturation based scaling, out-of-gamut scaling, and non-linear scaling. Of course, other scaling requirements may be desired and could be added as such. As further described herein, the non-linear scale module could be used to enhance dark color values and may depend on the luminance value of image data values. Once these scaling requirements are determined, there are a multitude of ways of combining them to create such a single scaling factor—including multiplying them or taking the minimum of them or a combination thereof.