slide scanner
Slide scanners are transmitted light scanners and shine through the slides, films or negatives to be scanned. These scanners can be flatbed scanners with a transparency unit, but also special scanners for large or small slides with magazines.
The main difference in the digitization of transparent 35mm slides and normal photographic originals lies in the resolution. Since the originals - slides, negatives, film strips - are only a few centimeters in size, a slide scanner must have a much higher resolution than a photo scanner. These are quite 4,000 dpi and higher.
In addition to resolution, sharpness of detail plays a decisive role. It is directly related to the focusing possibilities and the depth of field of the scanner, since the originals are often unframed and not completely flat.
The contrast range, on the other hand, is determined by the density, which results from the color depth. Slide scanners work with color depths of 8 bits, 12 bits and 16 bits per color, which corresponds to a total color depth of 24 bits, 36 bits or 48 bits. The density is a dimensionless value that is calculated from the logarithm of the color depth.