Contents Selection Intro- dynamic range Conversion Quality Control Metadata Technical Presentation Digital Preservation Management Continuing Education
Basic Terminology-file size

1. Basic Terminology

Key Concepts

digital images
pixel dimensions
bit depth
dynamic range

file size
file formats

additional reading



DYNAMIC RANGE is the range of tonal difference between the lightest light and darkest dark of an image. The higher the dynamic range, the more potential shades can be represented, although the dynamic range does not automatically correlate to the number of tones reproduced. For instance, high-contrast microfilm exhibits a broad dynamic range, but renders few tones. Dynamic range also describes a digital system's ability to reproduce tonal information. This capability is most important for continuous-tone documents that exhibit smoothly varying tones, and for photographs it may be the single most important aspect of image quality.

Dynamic Range: The image on top has a broader dynamic range, but a limited number of tones represented. The lower image has a narrower dynamic range, but a greater number of tones represented. Note the lack of detail in shadows and highlights in the top frame. Courtesy of Don Brown.

Reality Check

Which of the these images has the more limited tonal representation?

Answer (check one):

The image on the left

The image on the right

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Basic Terminology - bit depthBasic Terminology - file size

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