Calibrate Your Scanner

If you have trouble getting scans that look right, the problem may not be with your scanning technique. Calibrating your scanner can go a long way toward insuring that what you scan and what you see on-screen and what you print are all the same. Scanner calibration goes along with monitor and printer calibration to help get the best color match possible from three very different devices.

Color correction can be done within Adobe Photoshop, Corel Photo-Paint, or your other image editor of choice. However, if you find yourself having to make the same types of corrections over and over — scans that are consistently too dark or have a reddish cast to them, for example — calibrating your scanner can save much image editing time.

Basic Visual Calibration
The first steps in calibrating your scanner are to calibrate your monitor and calibrate your printer. The next step is to scan something and make adjustments until your scanned image, your monitor display, and your printer output all accurately reflect the same colors. This step requires that you first become familiar with your scanning software and the adjustments available.

If you've calibrated your printer by printing a digital test image (as described in Calibrate Your Printer), you can scan your print of that test image and use it to visually calibrate your scanner to the output of your printer. Or, use any high quality photographic image with a good range of tonal values. Before scanning for calibration be sure that all automatic color correction is turned off. After scanning, adjust the controls (on your scanner or within your scanning software) and rescan until what you scan matches your monitor display and printed output. Note all adjustments and save them as a profile for future use. Scan, compare, and adjust. Repeat as necessary until you are satisfied that you've found the optimal settings for your scanner.

Color Calibration with ICC Profiles
ICC profiles provide a way to insure consistent color. These files are specific to each device on your system and contain information about how that device produces color. If your scanner or other software comes with a pre-made color profile for your scanner model, it may give good enough results using automatic color correction.

ICC profiles
Get an ICC profile for your monitor as well as your printer, scanner, digital camera or other equipment.

Calibration or profiling software may come with an IT8 scanner target — a printed piece that includes photographic images, grayscale bars, and color bars. Various manufacturers have their own images but they all generally conform to the same standard for color representation. The scanner target requires a digital reference file specific to that image. Your calibration software can compare your scan of the image to the color information in the reference file to create an ICC profile specific to your scanner. (If you have a scanner target without its reference file, you can use it as your test image for visual calibration as described above.)

Scanner targets and their reference file can also be purchased from companies that specialize in color management.

Targets and Test Images
Whether visually or with color management software, target images provide a range of color and grayscale for calibrating monitors, printers, scanners, and digital cameras. Find free and commercial scanner targets, their reference files, and other test images.

Scanner calibration should be redone every month or so, depending on how much you use your scanner. And if you make changes to your software or hardware, it may be necessary to re-calibrate.

Calibration Tools
Color Management Systems include tools for calibrating monitors, scanners, printers, and digital cameras so they all "speak the same color." These tools often include a variety of generic profiles as well as the means to customize profiles for any or all of your devices.



***article from about.com