Instructs the scanner to scan the original within the single scan area with Grayscale composition. Grayscale composition uses 4 bits per pixel to represent 16 different shades of gray. At a resolution of 300 dots per inch, a grayscale scan records 1200 bits of information per inch for each horizontal inch scanned, or 360,000 bits per square inch.
Grayscale composition can be used for only one scan area. No other scan areas can be present. The scan area designated as Grayscale composition is indicated in the Scanner window by a wide dark dotted line.
When creating a Grayscale composition scan area, AppleScan enables the Contrast & Brightness settings. Choose Contrast and Brightness to set the contrast and brightness levels.
When a window contains a grayscale image, the window title in the View menu displays a Grayscale icon.
A grayscale image can be displayed on any monitor that can display 16 shades of gray, such as a color monitor or a high-resolution monitor. The correct monitor setting for the Macintosh II with an extended video card is 8-bits grayscale, 256 levels. You change this setting in the Control Panel.
If the monitor being used cannot display 16 shades of gray, AppleScan displays the image in black and white. Displaying the image as Line Art composition does not effect the grayscale information in memory or in a saved document.
Grayscale images can be converted to halftone or line art by using the Converter. A conversion can be performed immediately, or save the grayscale image and convert it at a later time.
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Preview
Instructs the scanner to perform a 75 dots per inch (dpi) resolution, 100% scale, in Line Art composition.
A preview is effected by the Threshold setting and the Graymap setting. Typically, Preview is used to obtain a rough scan image to set scan areas prior to using Scan.
A preview scans the entire scanner glass, ignoring any scan areas set in the Scanner window.
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If either of the following messages appear:
• "can't shade"
• "can't find home position"
turn the scanner off and then on again. If this doesn't fix the problem, return the scanner to your dealer for repairs.
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Click an item in the Scan Control Panel you would like information about.