Why is this the upper limit of resolution? According to the researchers, if the individual pixels where any smaller light would simply bounce off them and diffract, blurring the picture rather than sharpening it. And these aren't your average pixels either. Each is a tiny gold or silver nanodisk fixed to a tiny pillar. Color is conjured by adjusting each disks diameter and the spacing between it and its neighbors, creating an effect called plasmon resonance that is perceived by the eye as different shades.