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Cartegraph Campus

Contrast Ratio Calculation

The contrast ratio is the difference between the Background Ra and Legend Ra:

Estimated Contrast Ratio = Largest Estimated RA/Smallest Estimated RA where

  • Largest Estimated Ra is the bigger of the two Estimated Ra values.
  • Smallest Estimated RA is the smaller of the two Estimated RA values (not necessarily Background or legend just whichever is smaller)

If the value is 0 the contrast ratio is empty.

If Estimated Legend Ra or Estimated Background Ra is empty the Estimated Contrast Ratio is empty.