Editing RGB color model (section)

===RGB and scanners===
In computing, an [[image scanner]] is a device that optically scans images (printed text, handwriting, or an object) and converts it to a digital image which is transferred to a computer. Among other formats, flat, drum and film scanners exist, and most of them support RGB color. They can be considered the successors of early [[telephotography]] input devices, which were able to send consecutive [[scan line]]s as [[Analog signal|analog]] [[amplitude modulation]] signals through standard telephonic lines to appropriate receivers; such systems were in use in [[Publishing|press]] since the 1920s to the mid-1990s. Color telephotographs were sent as three separated RGB filtered images consecutively.

Currently available scanners typically use CCD or [[contact image sensor]] (CIS) as the image sensor, whereas older drum scanners use a [[Photomultiplier|photomultiplier tube]] as the image sensor. Early color film scanners used a [[halogen lamp]] and a three-color filter wheel, so three exposures were needed to scan a single color image. Due to heating problems, the worst of them being the potential destruction of the scanned film, this technology was later replaced by non-heating light sources such as color [[LED]]s.