User`s guide

Chapter 6:The Scanner Set-up Window
ScanShop User’s Guide - 49
The following table lists the bits per pixel and pixels per byte required for
different types of images:
Remember that the more information stored per pixel and the greater your dpi,
the larger your file size will be. An 8.5 x 11 inch image at 120 dpi and 1-bit
resolution will have a file size of 164K, at 4-bits 655K, at 8-bits 1.3 MB, and at
24 bits 4.0 MB. For a description of Bits per Pixel, please refer to “About
Resolution,” in the “Introduction to Imaging and Image Processing” chapter.
(The file sizes for 6 and 8 bits/pixel images are the same because 6 bit pixels are
stored in 8 bit bytes.)
Brightness
The brightness is set with a slider bar, with a higher degree of brightness at the
right end of the scale, and a lower degree of brightness at the left end of the scale.
Threshold
The threshold control, available on certain scanners for 1 bit/pixel scans,
determines the balance of black and white pixels in the scanned image. You can
specify a certain intensity as the threshold, and the scanner will convert all the
Table 1:
Image Type Bits/Pixel
Line Art/B & W Images 1
Grayscale (16 grays) 4
Grayscale
(64 grays) 6
Grayscale (256 grays) 8
Color
(16.7 million colors) 24
Figure 6-6 Selecting Brightness