Foveon - Why X3 is Better To capture the color that other image sensors miss, Foveon X3 image sensors use three layers of photodetectors embedded in silicon. The layers are positioned to take advantage of the fact that silicon absorbs different colors of light at different depths, so one layer records red, another layer records green and the other layer records blue. This means that for every pixel on a Foveon X3 image sensor, there's actually a stack of three photodetectors, forming the first capture system with a full-color image sensor.