Types of Photo Printers

Inkjet vs. thermal-dye (dye-sublimation) photo printers

Most portable photo printers produce 4-by-6-inch photo prints, wallet and passport sized photos, and some go a little larger. The HP Photosmart printers output a variety of sizes. Several models print 5-by-7-inch photos and some can also print 4-by-8-inch and 4-by-12-inch panoramic photos. All snapshot photo printers are portable to some degree (some can run on batteries and all can be plugged into an outlet), which allows you to take them on vacation or to a family reunion.

Many portable photo printers are able to read a variety of memory cards and/or hook up directly to your camera using PictBridge or a similar technology. However, before buying a photo printer, even if it's PictBridge compatible, be sure to verify that your camera is compatible or that your printer accepts the camera's memory card. Printers come with internal basic photo-editing tools, but for more elaborate adjustments, you need to use computer-based photo-editing software. Some photo printers allow you to print wirelessly with Bluetooth and other wireless technologies, but this often requires separately purchased accessories.

Two types of ink technology are available in photo printers: inkjet and thermal dye. Inkjet printers use ink cartridges containing three or five colors, and sometimes black. If you print a lot of black-and-white photos, inkjet printers are the better choice because they are better at grayscale images. Although prints from some inkjet printers, like the HP Photosmart A-series and Epson PictureMate models, can be nearly water and smudge-proof, that's not true of many older models. It depends partly on whether or not the ink is dye or pigment-based.

In thermal-dye (also known as dye-sublimation or dye-sub for short) printers, the dye is embedded in a roll of transparent film, called a ribbon. Heat causes the dye to sublimate (change from solid to gas) and transfer to the surface of a special, glossy photo paper, where it becomes solid again. Most thermal-dye printers use four passes to print -- three to lay down the primary ink colors and a fourth to add a protective coating. As a result of the coating, thermal-dye prints are said to be waterproof and resistant to both smudges and UV fading, but manufacturers also make these claims for most inkjets.

Inkjet and thermal-dye printing present very different experiences for the user; reviews indicate that these differences can be deemed highly important or completely negligible, depending upon individual likes and preferences. Thermal-dye printing requires several passes through the printer, resulting in longer print times -- some reviewers see this as a negative when lab quality prints can be had from much faster inkjet models. CNet.com's Melissa Riofrio, for example, calls thermal dye "wasteful" and "complicated," while admitting that it functions well. Thermal dye has print-quality advantages over inkjet; TrustedReviews.com's Simon Williams praises the technology for its ability to produce pixel-less photos -- no pesky dot patterns -- and richer, more realistic coloration.

Experts say both printing methods are capable of photo-lab-quality output. Most reviewers indicate that image quality is a matter of personal preference. Dye sub printers produce greater saturation (some say over-saturation), but inkjets are generally capable of finer detail.