Digital Photo Printers
One of the major differences is that traditional film is an analog medium and most computer printers are digital. When you take a picture with a camera, the light activates dyes in the negative, which form a continuous tone image. The actual shades of color and black are small enough to blend smoothly into one another. Digital images, on the other hand, are generally made up of dots of color and black, similar to the half-tone process used in printing pictures in newspapers, books, and magazines.
Photo printers address this in several ways. If they are inkjet printers, which form the image from dots of colored ink, they use extra colors in the print process, called photo inks, smaller-than-usual dots that blend better, and special printer driver software that produces images with little or no visible patterns, called dither patterns.
Other photo printers use a dye-sublimation process to produce an image that's almost the same continuous tone as a real photograph. And at least one printer actually uses instant film to "print" a photograph.
How To Shop For Photo Printers
If you won't want or need to use the printer for standard print jobs, consider a specialized photo-only printer. Generally, these produce near or actual continuous-tone prints using photographic or dye-sublimation methods. They are also likely to offer a smaller photo-size print format. As with the specialized inkjet photo printers, these smaller-format printer generally let you print directly from the camera or memory card, as long as your camera and printer are compatible.
4-color process - Almost all color printers use four basic colors of ink to produce a color image, mixing them to get different shades and colors. These four colors are cyan (a blue color), magenta (reddish purple), yellow, and black. 6-color processes add two additional shades of ink, usually a lighter shade of cyan and a lighter shade of magenta.
CompactFlash card - A type of memory card used in some digital cameras.
Memory Stick - A type of memory card used in some digital cameras.
Dithering - The process of mixing dots of different colors together to produce other colors. If the dithering is smooth, you don't see the dots. Photo printers generally produce little, if any, visible dither pattern in the light-colored areas where they are most noticeable.
Dye sublimation - A process that instantly vaporizes the ink so that it is deposited on the medium as a much more controlled area, rather than just a dot. Dye-sublimation printers can produce an almost continuous-tone print, but the ribbon and media are expensive.
Photo inks - A special ink cartridge set that contains six colors of ink, rather than the four colors most inkjet printer use.
Print media - The type of paper being printed on. Photo printers generally produce the best quality output on special glossy photo paper.
Resolution - How many dots per inch (dpi) the printer can lay down on the output media.How many dots per inch (dpi) the printer can lay down on the output media.
SmartMedia/ SDcard -
A type of digital camera memory card.