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Description / Abstract:
Aim
The purpose of the TC 1-80 work was to provide guidance to aid
the successful implementation of the experimental procedures
commonly used to measure spatial brightness. This was done through
a review of the procedures and conditions under which these
experiments have been carried out.
Spatial Brightness describes a visual sensation to the
magnitude of the ambient lighting within an environment, such as a
room or lighted street. Generally the ambient lighting creates
atmosphere and facilitates larger visual tasks such as safe
circulation and visual communication. This brightness percept
encompasses the overall sensation based on the response of a large
part of the visual field extending beyond the fovea. It may be
sensed or perceived while immersed within a space or when a space
is observed remotely but fills a large part of the visual field.
Spatial brightness does not necessarily relate to the brightness of
any individual objects or surfaces in the environment, but may be
influenced by the brightness of these individual items (Fotios
Atli, 2012).
Evaluation of spatial brightness is a subjective assessment and
experimenters need to be aware of the limitations of such
assessments as can be observed through two statements:
Quantitative subjective assessments are almost always
biased, sometimes completely misleading.
[Source: Poulton, E.C., British Journal of Psychology, 1977; 68;
409-425]
In the study of perception, I think we get caught up a
little in thinking that much has to do with what people see.
Sometimes the procedural matter is more about influences on what
people say, rather than what they see.
[Source: Niall, K., TC1-80 member, June 2011; feedback on an
early draft]