Grayscale
An image mode that scans only the brightness data of an image and reproduces the image in white, black and 254 shades of gray (256 tones or 8 bits).
Histogram
A graph indicating the distribution of brightness data in an image. A dot is assigned a brightness value ranging from 0 (shadows) to 255 (highlights). The histogram shows how much image data there is at each brightness value. Adjusting the histogram changes the image contrast.
Image File
Images are expressed as collections of dots with varying color and brightness values that are digitized in particular formats for processing by a computer. At the most basic level, an image file contains bitmap information, which is the color information for each dot in each column and row of an image. The various file formats (TIFF, BMP, etc.) use different methods of storing and recalling this information.
Magnification
An expression of the relationship between the scanning resolution and the output resolution stated as a percentage. If the output resolution is set to 720 dpi and the scanning resolution to 360 dpi, then the magnification rate is 50%.
Moiré
The patterns or lines created by overlapping dots in an image. This phenomenon is found when photographs or pictures are scanned from books and magazines at low resolutions. The Descreen function helps to eliminate moiré patterns.
Optical Resolution
An expression of the volume of data per inch (dpi) that can be sampled by a scanner.
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