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Glossary: V

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Vacuum table (scanning)
A flat printing base with a series of small, finely spaced holes in its bed attached to a vacuum system. Works, such as photographic prints or maps, are placed on the table to make them lie flat. Vacuum tables used for this purpose often allow the user to adjust the level of vacuum…
The process of evaluating a process or product to ensure compliance with requirements or specifications.…
Vector data
Data that consists of mathematically described lines and curves. These mathematical representations are not composed of data that is mapped to individual pixels, as is bitmapped or raster data). For this reason, vector data can be scaled (changed in size) without loss of image quality. The data can be modified by changing the…
See Also Raster data; Vector image
Vector image
Image based in vector data.…
See Vector data
Video description
As described in Twenty-First Century Communications and Video Accessibility Act of 2010 (CVAA) also known as 47 CFR Part 79, \"although the CVAA uses the term \'video description\' in this context, the Commission has long considered the terms 'video description' and \'audio description\' to be synonymous.\" Moreover, 47 CFR Part 79 states that \"throughout…
See Audio description
Viewing booth
A enclosed or semi-enclosed area with controlled lighting that is used as a consistent and controlled environment for evaluating visual objects, such as original prints and paintings as well as reproduction prints, and to compare originals with reproductions. Viewing booths are generally illuminated using known, standardized lighting such as D50 or D65 lighting.…
Viewing file
See Derivative file
A darkening or reduction in saturation towards the outer edges of an image compared to the center.…
Virtual reality
Technology that allows a user to interact with a computer-simulated environment. Most current virtual reality environments are visual experiences displayed on a computer screen or through stereoscopic displays, but some simulations include additional sensory information, such as sound.…
Virtual replica
A copy that represents the entirety of a physical item in image form. Microfilm copies of books (especially brittle books), newspapers, and manuscripts are one type of virtual replica, and they have been a staple output of library and archive preservation programs for many years. Most digital copies produced by libraries and archives today…
See Also Physical replica; Museum-quality facsimile or print; Copy negatives and transparencies; Interpositives, duplicate negatives and transparencies
Visible spectrum
The band of electromagnetic radiation that human eyes can detect. This ranges from wavelengths of approximately 400 to approximately 700 nanometers (nm). Normal human vision responds slightly beyond this range to both shorter and longer wavelength radiation, but with very little sensitivity. Maximum sensitivity of the human vision in bright-light conditions is…
Visually lossless compression
See Compression, visually lossless
Voting engine
See OCR voting