"Cousin Ricky" <rickysttATyahooDOTcom> wrote:
> Further testing with both media absorption and fade_color confirmed my
> suspicion.  With tricolor rendering, transparent objects with colored interiors
> show a bias towards the most prominent primary color.
>
> [snip]
>
> The bias in the upper left image isn't nearly as strong as in the tests I did
> years ago, but more recent testing revealed that the bias is less strong for
> fade_colors at less than full strength (that is, fade_colors whose value is less
> than 1.0 when converted to HSV).

The attached image shows one of my fade_color tests.  The circled number is the
nominal hue (with assumed_gamma set to 1) of the entire suite.  The other
numbers along the left edge show the depth, in POV units, of the samples in each
row.  The top and bottom swatches of each column show the fade_color that was
used for that column.

The material for each sample is:
  ____________________

  pigment { rgbt 1 }
  interior
  { fade_distance 1
    fade_power 1001
    fade_color <color>
  }
  ____________________

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