Reprinted from TidBITS#700/06-Oct-03; reuse governed by Creative Commons license. TidBITS has offered more than fourteen years of thoughtful commentary on Macintosh and Internet topics. For free email subscriptions and access to the entire TidBITS archive, visit www.tidbits.com.
by Charles Maurer
Photos on a computer may look nice, but they're hard to tape to a refrigerator door. Sooner or later, most people who buy a digital camera hanker for prints and a photo printer – and then for aspirin once they start trying to figure out which one to buy. Every model sounds wonderful and every article reviewing them says that different models are best. In this article I shall to try to sort out some of this confusion. I shall explain how photo printers work, what to look at and what to ignore, and how to get the most out of them. Toward the end I shall discuss my own purchasing decisions and review several printers. Along the way I'll mention some useful software as well.
Overview of the Technology — Let's begin with some basic technology. Heat a transparent yellow ribbon until dye comes off and transfers to some paper, then heat a magenta ribbon, then a cyan ribbon, and finish off with a transparent one. The three dyes will form every colour and the transparent one will apply a protective film. Since the dyes are transparent, the colours will not be particularly dense, but no dots will be visible and the pictures will look like conventional photographs. This technology is called dye sublimation.
Dye-sublimation printers are the simplest to use and maintain. You merely snap in a cartridge containing a parti-coloured ribbon and replace the cartridge when the ribbon runs out. They cost more per print than ink-jet printers but only if you always print enough to use up your ink cartridges before they dry out. They cannot produce the ultimate in quality, but the prints resemble those from a commercial photofinisher and they are tough. They are ideal for snapshots and for 8″ x 10″ prints that will be handed around.
Although dye-sublimation prints can be very good, the highest quality possible comes from inks. Ink-jet printers use the same three colours but their inks are more opaque, so these printers do not superimpose the colours, they apply dots of colour adjacent to one another. This means that dark greys formed by three inks would have to incorporate yellow dots. Those yellow dots would limit contrast and soften edges, so ink-jet printers incorporate a fourth ink, black, into dark greys and blacks.
Cheap ink-jet photo printers use just those four inks: yellow, magenta, cyan and black. Those four are sufficient to form a complete range of colours and can be fine for snapshots, but if you look closely at light tones, you will see dots. That's because …
