This disclosure provides systems, methods, and apparatus related to electromechanical systems display devices. In one aspect, an apparatus includes a display assembly, a sensor, and a processor. The display assembly may include an array of electromechanical systems display devices. The sensor may be configured to provide a signal indicative of an illumination angle, a viewing angle, or both, with respect to a line perpendicular to the display assembly. The processor may be configured to receive the signal from the sensor, to determine the illumination angle and/or viewing angle, and to process image data to compensate for the determined illumination angle and/or viewing angle. In one implementation, the image data is processed to compensate for a shift in a wavelength of light reflected from at least one of the electromechanical systems display devices that would have occurred as a result of a non-normal illumination and/or viewing angle.