Photomultiplier Tubes (PMT) Sensor

Characteristics

The photomultiplier tube (PMT) is an ultra-fast photo-resistant electronic vacuum tube that is used in scanners. PMT sensor capture a single pixel at a time.

PMT scanners are very sensitive to light, which helps them distinguish between changes in light intensity measured at each pixel. This sensitivity allows PMT drum scanners to have a density range of 3.8 or higher. Having a higher density range enables PTM drum scanners to capture more detail at both ends of the spectrum and capture a greater range of colours in the picture.

Resolution

Resolution is the quantity of pixels per inch (ppi) that a scanner reads and records from the original image. The main advantage of the PMT technology is its ability to greatly enlarge the originals while still maintaining a superior resolution. For example, if a drum scanner could produce a resolution of 5000 dpi, this resolution will be the same for an image of any size. It won't make a difference whether the original is a 1-inch image or a 12-inch image. This means that a company can blow up an image quite large and still maintain good resolution. If we are to divide 5000 by 300, we get 16.67, which means a company that wishes to have a minimum of 300 resolution can enlarge their image up to a whopping 1667%!