1. A portable electronic device comprising: a display; a light sensor configured to sense an ambient light color condition; a processor configured to: determine an ambient light history including a plurality of ambient light color conditions, including a plurality of correlated color temperatures and luminance data, sensed over a duration of device operation by a light sensor; read a display-ready image from an image source, the display-ready image having a plurality of pixels; adjust a manner in which the display-ready image is displayed on the portable electronic device by color-shifting at least a subset of the plurality of pixels based on the plurality of ambient light color conditions in the ambient light history to thereby generate a color-modified image, wherein color-shifting the subset of the plurality of pixels includes adjusting white points of the subset of the plurality of pixels; display the color-modified image on the display of the portable electronic device; detect a threshold brightness decrease during a predetermined time period based on the luminance data in the ambient light history; and apply a dimming pattern with a target brightness that varies with time to effect a graduated dimming of the brightness of the display over a predetermined time in response to the detection of the threshold brightness decrease.