Contrast

Contrast refers to the differences between luminances and is used as a factor or a ratio.  The highest contrast ratio obtainable is the ratio between maximum and minimum luminance in an image. In plain language, it’s the difference between the maximum white and (minimum) black luminance level, expressed as a ratio between the two.

There are some essential points to understand about contrast:

Projector contrast ratio. The contrast figure in brochures is typically an on/off number (i.e. measurements taken at different times, representing the difference between a full white image and a black image). This can generate ratios such as 5,000:1 or greater, which do not relate to real life measurements at all. The only usable contrast data is the difference between the black levels and the white levels – on the same image. In this real life scenario you will rarely measure about 100:1. At time of writing, the authors have never measured over 200:1 contrast ratio (using proper ANSI methodology).

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