Shades of brown can be produced by combining red, yellow, and black pigments, or by a combination of orange and black—illustrated in the color box. The RGB color model, that generates all colors on computer and television screens, makes brown by combining red and green light at different intensities. Brown color names are often imprecise, and some shades, such as beige, can refer to lighter rather than darker shades of yellow and red. Such colors are less saturated than colors perceived to be orange. Browns are usually described as light or dark, reddish, yellowish, or gray-brown. There are no standardized names for shades of brown; the same shade may have different names on different color lists, and sometimes one name can refer to several very different colors. The X11 color list of web colors has seventeen different shades of brown, but the complete list of browns is much longer.