A backlight assembly and a display including the same are disclosed. In another general aspect, a method includes dissolving glaserite in water at an elevated temperature to produce a saturated or nearly saturated solution, and cooling the solution to a temperature where potassium sulfate and mirabilite will crystallize from the solution as stable phases. A roll compensation value is established that is a constant in view of the fixed angular offset. Test data is then summarized using histograms representing time windows of data and data within the test histograms are clustered.