Guidelines for Electronic Preservation of Visual Materials
Appendix D: A Basic Digital Imaging Glossary
Pixel, Pel (abbreviation of Picture Element)
A dot that can vary in brightness and/or color.
Digitized Image
A two-dimensional array of pixels.
Color Image
A digitized image that can vary in brightness and color.
Grayscale Image
A digitized image which contains pixels which vary only in brightness
in fine steps from black to white.
Binary Image
A digitized image which contains pixels which may only be fully
black or white.
Spatial Resolution
The number of pixel spaces used in sampling a unit length of the
image.
Tonal Resolution (or Pixel Depth)
The number of bits required to represent the number of distinguishable
shades preserved in the image.
Table of Contents - Executive Summary - Introduction - Aspects of Collection Analysis - Guidelines - Scanning & Compression - Appendixes