How do I choose a scanner?

Decide what you want to scan.

Will you scan photographs, negatives or slides?
- Photographs produce better quality scans than prints from an inkjet printer.
- Negatives produce better quality scans than photographs but are trickier to scan.
- Slides are the hardest to scan.

Types of Scanners

Flatbed scanners work best for photographs and are the most affordable.
- Look for one with CCD (charged-couple device) instead of CIS (Contact Image Sensor) technology.
- Some scanners have transparency adapters for scanning negatives and slides but they add to the cost.
Negative or slide scanners are also available; they have the highest resolution, but are the priciest.
Some photo labs scan photographs and negatives and will burn them onto a CD.
- Check their prices before dropping off photographs, negatives or slides.

Maximum scan area
What size media will be scanned?

Most lower priced scanners will scan an image up to 8.5 x 11 inches.
Some will scan up to 8.5 x 14 inches (legal size) or larger but are much more expensive.

Resolution - Optical or Interpolated?
What are the images being scanned for: the web, an e-mail to grandma or the yearbook?

Optical resolution is the most important and is measured in dots or pixels per inch (dpi or ppi).
More pixels will generate better image quality.
Resolution is shown as a horizontal and vertical measurement, for example 600 x1200, but go by the smaller number.
Purchase a scanner with a higher resolution if scanning fine objects, small fonts, line art or if the image will be enlarged.
An optical resolution of 600 dpi should be the starting point.
For negative or slide scanners, start at 1200 dpi.
Scan at a higher resolution than you will print to get the best image quality.
Interpolated resolution is software-enhanced resolution.
- Optical resolution is a better indicator of image quality. Ignore this number.

Bit Depth

Bit depth is the number of bits of information a pixel can remember.
- The higher the bit depth, the more colors that can be distinguished, which produces a better quality image.
The minimum bit depth to start at is 24, which theoretically can produce 16.8 million colors.
- Even though your monitor or printer may only be able to handle 24 bits, a higher bit depth, 30, 32, 36, 42 or 48, will produce a better quality image.
When scanning negatives or slides, look for a scanner with a bit depth of at least 30 or 36.

Dynamic Range

The dynamic range or optical density is measured from 0 - 4.
It is the difference between the darkest and brightest optical densities the scanner can capture.
It may not be mentioned in the specs.
Flatbed scanners - look for a number between 2.8 - 3.0.
Slides - look for 3.2
Negatives - look for 3.4

Software

Many scanners are TWAIN compliant meaning they work from within many graphics programs.
- Look for a scanner that is TWAIN compliant.
Software is packaged with the scanner. Make sure the software will work for your needs.
- Any image that is scanned will lose a little information or be a little blurry. The proper software can correct most of this loss if used correctly.

Connecting to the computer

Scanners come with SCSI (fast), USB (faster) or FireWire (fastest) connections.
Check the computer's ports to make sure the scanner can be plugged in once purchased.

Storage

Scanned images take up a lot of space
- Make sure the computer has a large hard drive.
Scans should be archived.
- Have a CD burner or other removable media available to store the images.

Memory

Large images need a lot of RAM to open them.
Take the size of the file and double it to get the amount of RAM needed to open a file.

Warranty

Compare warranties on scanners.
Better warranties cover parts and labor and will vary with manufacturers and the quality of the scanner.