It's in the eyes of the beholder!

by Jeffrey B. Dalin, DDS, FACD, FAGD, FICD

For the past eight months, I have been extolling the very real benefits of digital radiography and digital photography. It is one thing to capture digital images and display them on a computer workstation. The on-screen images are clear, uniform, and sharp. View them on a good-quality monitor or flat screen and I have little doubt that you will be anything other than impressed and find the images extremely useful in the diagnosis and treatment of patients.

However, there seems to be a great amount of confusion when it comes to printing these images. I hate to hear someone say that digital radiography does not produce good-quality images. Digital radiography produces top-quality images ... people just do not know how to reproduce these images on paper!

Two main factors determine the quality of the printed images: the printer and the paper. The level of training and knowledge that you and your staff possess are two other important factors.

Inkjet printers use microscopically small droplets of ink to form letters and graphics. Most inkjet printers use two cartridges to supply these droplets: one with black ink and one with colored ink (cyan, magenta, and yellow inks). Newer models use dye sublimation to place the ink onto paper. Laser printers work much like a plain-paper copier, forming images by transferring toner onto paper passing over an electrically-charged drum. This process can give you sharp black and white text and graphics, but printed images are generally not of diagnostic quality. Use a laser printer at your front desk for management of your office. To print diagnostic-quality images, I strongly recommend that you only use a high-quality inkjet printer.

Printers differ in the fineness of detail they can produce. The main measure of print quality and sharpness of images is known as resolution, which is expressed in dots per inch (dpi). The larger the dpi, the sharper the image.

Choosing a good quality paper is crucial to reproducing the highest quality final image. Photocopier paper just isn't going to cut it! This is true for digital radiography, as well as for digital photography. There is a good reason that images printed out on ordinary paper come out blurry and washed out. Ink tends to "bleed" into the rough surfaces of ordinary paper. Inkjet paper or photo paper is coated with a glossy surface that "holds" the ink in place, creating greater image detail. HP, Epson, and Kodak all make fine, quality glossy paper suitable for this purpose.

As a general guide in the selection of an inkjet printer, I encourage you to consider the better quality models from Hewlett-Packard or Epson. Expect to pay in the range of $250-$350 for a local printer or $700 or so for a network printer. Kodak has cleverly modified a Lexmark printer for printing digital radiographs. Its DMI 1200 printer utilizes image-processing software algorithms that are designed to support attributes important in dental X-ray images, such as superior image contrast and edge enhancement. Despite network limitations, I like this printer very much. The Olympus P400 Dye-Sublimation printer is a good alternative for those who are worried about long-term ink stability when printing photographs. As you can see, there are numerous models on the market that can do a great job for you.

One last set of tips. When printing digital radiographs or photographs, the key is to set your printer at its highest resolution or best-quality setting and use glossy photo or premium inkjet paper. When printing radiographs, make sure the printer is set on black ink and not color ink. At the highest quality settings, the digital radiographic and photographic images produced will be crisp and clear and something to be proud of.

Jeffrey B. Dalin, DDS, FACD, FAGD, FICD, practices general dentistry in St. Louis. He also is the editor of St. Louis Dentistry Magazine and spokesman and critical-issue-response-team chairman for the Greater St. Louis Dental Society. His address on the Internet is www.dfdasmiles.com. Contact him by email at jeff@dfdasmiles.com, by phone at (314) 567-5612, or by fax at (314) 567-9047.

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