In the fully digital darkroom there are 3 main components to the system --> your camera, software and the printer. The software component can take many many shapes and complexities including image editing, filtering, cataloging and organizing. The film-based digital darkroom is a bit more complex with a total of 5 components --> camera, output, scanner, software and printer. I'm going to try to cover each of these 5 sections with enough detail to give you an understanding of how to make decisions to create your darkroom setup. We're going to start off reviewing what a scanner is and how it works, which should give you some information about what to look for when looking to add a scanner into your photography outfit.

What exactly is a scanner. A scanner is a device that inputs graphical data into a computer [in its simplest descriptive form]. This input can be used for virtually everything from Desktop Publishing to photography (this the inclusion here). The actual # of uses for a scanner are virtually endless, including that of a paperweight, so there has become a degree of specialization within the scanner category:

High-end Drum Scanner
These scanners are typically very high quality scanners used in the publishing industry. The technology used in these scanners is PMT (photomultiplier tube). These scanners can very versatile, capable of scanning transparencies, reflective art, 35mm slides, etc. at resolutions up to 10,000 dpi.

Desktop Document Scanner (Flatbed and Sheet-fed scanners)
This is the most common scanner

Photo Scanner
These scanners are typically sized for 3x5-1/2 and 4x6 photos. The scanning takes place by passing the photo over a stationary light source which is used to capture the image.

Slide/Transparency Scanner
This type of scanner works by passing light THRU an image rather than reflecting it.

Handheld Scanner
This type of scanner contains the same techonology as the desktop document scanners, but rely on the user to move the scanner rather than having a motorized belt to move either the scanning sensor or the document itself. This type of scanner typically has a poor image quality and is most useful due to its portability.

Now, let's start to understand how a scanner works. All scanners work relatively the same, by reflecting light over the document or 'thing' that is to be scanned. Based on the amount of light that gets transmitted, the sensor within the scanner will convert the image into a digital document, or an image. There are 3 types of scanning technologies available today:

PMT
Photomultiplier Tube. This technology is utilized by the high-end drum scanners. This is the most expensive of the 3 different technologies available and is not normally used by consumers, so i will leave detailed descriptions of this technology to others.

CCD
Charge Coupled Device.

CIS
Contact Image Sensor.