Glossary - Microtek ScanMaker IIG User Manual

Appendix J

Glossary

Cross-referenced entries are indicated in bold type.
Bit
The smallest unit of memory in the computer. A bit can be either off or on,
representing a value of 0 or 1. Greater bit-depth translates to more com-
plexity in image information. Some examples:
Single-bit
Single-bit images use just one bit of data to record each pixel — either
black or white.
8-bit grayscale
Images that contain 256 (2
represent most black-and-white photos accurately. 256 levels of gray is
actually more shades of gray than the human eye can see.
24-bit color
24-bit color images are composed of three 8-bit color channels. When
combined, the red, green and blue channels provide up to 16.7 million
possible combinations (hence, colors). 24-bit color is also known as True
Color and photo-realistic color.
36-bit color
36-bit color images are composed of three 12-bit color channels. When
combined, the red, green and blue channels provide up to 68.7 billion
possible combinations that translate into that many "colors." (This com-
pares to 16.7 million colors for 24-bit scanners.) The extra amount of
information that can be processed by 36-bit scanners translates to more
vivid color reproduction, as the scanner is able to accommodate more subtle
gradations of color approaching lifelike accuracy.
Auto Document Feeder (ADF)
A scanner accessory that helps with text scanning. The ADF allows
continuous scanning of up to 50 pages of text. This accessory is normally
used with an OCR (Optical Character Recognition) software program, not
an image-editing program like Adobe Photoshop or Microtek ImageStar II.
Brightness
The balance of light and dark shades in an image. Brightness is distinct
from contrast, which measures the range between the darkest and lightest
shades in an image. Brightness determines the intensity of shades; contrast
determines the number of shades you get.
8 =256) possible shades of gray needed to