If using other color spaces, see Understanding Success Criterion 1.4.3 . Note 4 If dithering occurs after delivery, then the source color value is used. For colors
      that are dithered at the source, the average values of the colors that are dithered
      should be used (average R, average G, and average B). Note 5 Tools are available that automatically do the calculations when testing contrast and
      flash. Note 6 A separate page giving the relative luminance definition using MathML to display the formulas is available.