User manual

27 • TROUBLESHOOTING
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ColorQuartet 5.0 Pro
27•Troubleshooting
Suppressing film grain in smooth image areas
Some images have large areas of the same color, such as a blue sky, that should remain smooth
in the reproduction. If such an image is scanned at high resolution, the high resolving power of
the scanner’s optics may make the film grain visible.
In such a case, there are several methods you can use to suppress graininess and smooth out the
image.
The techniques listed below are for transmission originals. For reflectives, use the Descr
een
function in the Special Functions section of the
Scan Setup window to digitally defocus the
image slightly.
• Super Sampling: If your scanner supports the Super Sampling
function in the Unsharp Masking
window, try setting Super Sampling at 4. The scan will take longer, but the image will be
smoothed without any reduction in sharpness.
• Mounting gel: Using a drop of mounting gel or oil between the original and the glass of the
scanner’s mounting plate or drum will not only smooth out graininess somewhat, but will also
prevent scratches and dust from showing in the scan. If you have a flatbed scanner, mount the
original in gel or oil on the bottom glass plate of the mounting plate. Remove the top glass plate
and use a mounting foil instead (with a drop of gel or oil between the original and the mount-
ing foil, too). This will make it easier to smooth out the “sandwich” and avoid air bubbles. To
remove residues of gel or oil from the scanner and the original, use Film Cleaner (never Drum
Cleaner!).
• Focus Elevation: This method defocuses the scanner mechanically. If you can’t use either of
the techniques mentioned above (or don’t want to), setting F
ocus Elevation to about 20 for a
flatbed scanner or about 50 for a drum scanner will smooth out the image without removing
too much sharpness. Be careful to use only a little or no unsharp masking, and if you have a
drum scanner, don’t use the smallest
aperture.
• Despeckle: You can also scan the image as usual and then open it in Adobe Photoshop, where
the “Despeckle” function will help smooth out graininess.