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equivalent contrast, C̃

[5.9.14.4]

A numerical description of the relative visibility of a task. It is the contrast of the standard visibility reference task giving the same visibility as that of a task whose contrast has been reduced to threshold when the background luminances are the same.

This term is obsolete.

NOTE: This definition was changed in ANSI/IES RP-16-17 Addendum 4.

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