Inkjet printers operate by propelling variably-sized droplets of liquid or molten material onto almost any printable material. They are the most common type of computer and consumer printer due to their low cost, high quality of output, capability of printing in vivid color, and ease of use. There are three main technologies used in contemporary inkjet printers: thermal, piezoelectric, and continuous. Desktop inkjet printers, as used in offices or at home, all use aqueous inks. These inks are inexpensive to manufacture, but are difficult to control on the surface of media, often requiring specially coated media and sensors to control the quality and position of them. Inkjets can print finer, smoother details through higher print head resolution, and consumer inkjets with photographic-quality printing are widely available. Inkjets have the advantages of practically no warm-up time and lower cost per page. To keep overall printing costs low, efficient power supplies and intelligent power management such as fast wake-up and auto-power-off are essential.