Dye-sub printers use a transfer ribbon made of a plastic film. This film contains layers of cyan, magenta, and yellow dye. A thermal print head, containing thousands of heating elements capable of precise temperature variations, moves across the transfer ribbon. Heat from the heating elements cause the dye on the ribbon to vaporize and diffuse onto the surface of specially coated paper. The varying densities of color are achieved by precisely controlling the temperature of the heating elements. The hotter the heating element, the more dye is vaporized and diffused onto the paper's surface. Most dye-sub printers use a three-pass system, layering cyan, magenta, and yellow dyes on top of one another. A clear coat is then added to protect the print against ultraviolent light.

The dye-sublimation technique produces a smooth or continuous tone image free of dithering, such as used by inkjet printers. The vaporized colors permeate the surface of the paper, creating a gentle gradation at the edges of each pixel. Because the color infuses the paper, it is also less vulnerable to fading and distortion over time. The typical print resolution of dye-sub printers is 300 by 300 dpi, although there are some with a little higher resolution. The average time to print a picture is typically 2 to 3 minutes per print.

Printers based on the dye-sublimation technique are expensive to manufacture and the cost increases as the size of the printing area gets larger. Most dye-sub printers are limited to 'snapshot' size, that is, 4- by 6-inch prints or smaller. These printers typically cost in the range of $300 to $400. There are a few that print larger sizes and, as expected, cost a few hundred dollars more.

In addition to the initial cost of the printer, you must consider the cost of supplies, that is, paper and a ribbon cassette. The cost varies with the quantity of sheets in the package and the size of the sheets. For example, a package of 25 4- by 6-inch sheets with a cassette typically costs $20. This works out to about 80 cents per print. A package of 25 8.25- by 11.7-inch sheets with a cassette typically costs $100, which works out to $4 per print.

Depending on the model, dye-sub printers can be interfaced to a computer or operated standalone. When interfaced to a computer, a user can print images obtained from multiple sources, such as a digital camera, scanner, Internet, or e-mail. For those printers that operate in a standalone mode, one or more slots are provided for accepting various types of memory cards, such as CompactFlash, SmartMedia, or PC Card.

Dye-sub printers that accept digital camera memory cards usually support Digital Print Order Format (DPOF). DPOF is a system included with many digital cameras that allows the user to select (tag) images that are to be printed, enter the number of copies of each to be printed, and choose whether or not to print the date and time with them. This information is saved in the card for later printing from a printer or at a photo lab that supports DPOF. When inserted in the printer, the tagged images are printed. Some printers let you use a TV screen to view and select the images to be printed.

There are several manufacturers of dye-sublimation printers. They include: Acer (www.acer.com), Canon (www.canon.com), Olympus (www.olympus.com), Panasonic (www.panasonic.com), and Sony (www.sony.com).

Dye-sublimation printers offer an alternative method for producing pictures. The quality of the pictures produced is excellent. However, the latest generation of inkjet photo printers also produces excellent pictures. Dye-sub printers are more expensive than inkjets and the cost of supplies is also greater. However, they are smaller in size and thus, more portable. Most of them can be operated in a standalone mode, so a computer is not required.

T. Zinneman is a CCPCUG member. If you have any questions or comments, please send them to tzinneman@home.com.

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