Canon CanoScan N1240U User Manual page 96

Glossary
Contents
Troubleshooting
Glossary
Index
Grayscale
Grayscale refers to a single-channel image made up of 256 shades of gray,
ranging from white to black, that represent all tones in an image.
Halftoning
A method of simulating intermediate tones in black-and-white images by
varying the patterns dots and lines. Halftoning is usually used for
photographs, or other images with intermediate tones, scanned in Black
and White.
Height
The Height text box contains the height of the current selection, or, if there
is no selection, the maximum vertical output size, based on the currently
selected Paper Size.
Histogram
The Histogram displays the distribution of bright and dark pixels for each
color channel in the previewed image. The Eyedropper tool on the
histogram graph lets you redefine the tonal profile.
Keep Proportions button
The Keep Proportions button affects the selection and the Width and
Height text boxes. When you click the Keep Proportions button, the image
size is maintained in the same proportion whenever you change either the
width or the height.
Low contrast
An image that has low contrast does not have many distinct differences
between tones.
Magazine-Reduce Moiré / Descreen
Moiré patterns are caused by poor dithering as a result of scanning images
from published materials like newspapers, magazines, books, etc. When
this feature is on, moiré reduction smoothes the overall appearance of the
image and enhances image quality.
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