Does dimming LEDs cause color shifts?
Changes in the current through an LED affect the junction temperature of the device, which can shift the spectral power distributions (see How are LEDs affected by heat?). Red and yellow AlGaInP LEDs have larger spectral shifts than blue, green and white InGaN LEDs (Stringfellow and Craford 1997), but none of these sources undergo a degree of color shift comparable to the color shift experienced when dimming an incandescent lamp. Differences among various colored LEDs could be problematic in arrays designed to mix colors to produce white light. Color appearance could shift unacceptably when dimming if the different color components change.