The image above is a massively enlarged version of the famed Lenna test image printed with the method, which is just 50x50 micrometers — that's 0.05 millimeters in either direction. Each pixel is just 250x250 nanometers. In order to create this level of optical density, the team has discovered a method which lets them pick and chose which colors are reflected. Each pixel is made up of four nanometer scale columns, capped with silver and gold. By varying the height, width, and space in-between the columns, the researchers were able to accurately control what spectrum of light is reflected.