The images on this page are a net for the RGB colour cube. If printed and folded up into a cube, they show you what the colours at the boundaries of RGB colour space look like. (NB You will need a photographic quality printer to achieve a reasonable result.)
The image exists in two versions: a 32-bit RGB + alpha image, and a 24-bit RGB image, both of 768 by 1024 pixels. The 32-bit image includes transparent areas (using the alpha channel). Depending on the software that you use to view Web pages, and its settings, you may or may not see the transparent areas correctly. Instead of seeing the page background through the transparent areas, you may see a default background colour. In the 24-bit image the areas outside the net are coloured white. The images use the sRGB colour space.
Note that, because of the very large number of colours in these images (393216) you will see the images correctly only on a display that has 24-bit RGB graphics. If you have 16-bit graphics or less, you will see banding or contouring within the image.
Each image contains black fiducial marks of one pixel width in the corners. (These may not be correctly displayed in a Web browser.) These marks are to aid in cutting out the net from a printout, and to indicate clearly that the whole image has been printed. (We had problems ourselves with part of the edge of the image not being printed, which we didn't discover until we folded up the cube and found some of the sides to be short.) Since the marks are within the image boundary, you should cut outside the marks.
These images are made freely available, but I retain copyright in them. If you use them in a publication, all I ask is that you credit the source of the original image.
The images are available in Portable Network Graphics (PNG) format only (PNG home page, UK mirror). If you need a different format you can convert it using an image viewer or editor.