Which scanner is right for you? Armed with a few basics you can make a good choice and then start digitizing your snapshots. To keep it simple, we’ll talk about flatbed scanners.

How does a scanner work? You place the photo flat, face-down on the clear glass scanner bed and close the lid. A light source travels down the photo. The light reflects off the photo and back onto sensors, like the photosites we talked about in digital cameras. The scanner creates red, green and blue versions of the photo and merges them together to create the digital image that ends up on your computer. See, that wasn’t so hard…

As you look at the many scanners out there, you’ll see them categorized by that pesky “resolution” thing. For example, let’s say a scanner boasts 1600 x 3200 dpi (dots per inch). The first number is the number of photosites on the scanner’s sensor. The second number is the distance the light source advances between scans. In this case, the sensor moves 1/3200 of an inch between each scan. Another measure of resolution is known as “bit depth”. Bit depth refers to the range of color that can be captured in a given pixel. Basically, scanners with higher bit depths (24-bit would be good for snapshots, 48-bit is the best if you can afford it) produce better color images (and bigger file sizes, ‘cause there’s more data).

How do you use this information to choose a scanner? Here’s some guidelines. If you want to scan family snapshots to make snapshot-sized prints later, a 600 x 2400 scanner would most likely fit your needs. If you’re going to scan slides or negatives with a transparency adapter, you’ll need at least a 1200 x 2400 scanner to make 3” x 5” prints later. With the newer 2400 x 4800 scanners, you can scan to make good-looking 8” x 10” prints later.

Another factor to consider is how your scanner will connect to your computer. There’s USB 1.0, which is the cheapest and slowest, but most common today. USB 2.0 is much faster, is becoming the standard on most PCs, and not much more expensive. FireWire is about the same speed as USB 2.0, but FireWire scanners are quite expensive. Finally, there’s the old standard, SCSI, which is faster, but most of today’s computers require an additional connection card to use it. For most consumers, USB 1.0 will provide adequate data transfer rates.

Something else to look into is whether or not the scanner software you’re going to use is TWAIN compliant. TWAIN is a set of standards that were developed to make sure that different scanners, software and operating systems could talk the same language to each other. The standard has been widely adopted, but it’s worth checking.

Speaking of scanner software, here’s some tips to save time and drive space when scanning your photos:

Although your scanner may have very high resolution capabilities, you don’t always need to use all the power. For example, when you scan a snapshot-sized photo, and you only want to be able to print it in its original size later, select a 200 or 300 dpi resolution with your scanner software. Any more than that will not add to the quality of the printed image later, but will significantly increase the file size of the digital image. Storage space costs money, whether you’re burning your archived photos to CD or storing them on a hard drive.

Finally, most scanning software gives you the option of cropping your photo before scanning, again saving time and file size.

© 2003 Peter F. Zimowski