Mixing Colors in Unity, Water-Color style, by (negative) Averaging!

MixColors.cs

// Calculates the average of all colors in the list.
// Normal averaging would yield additive color mixing,
// ... i.e. the way *light* of color would mix.
// Colored liquids, like water colors, mix in a 
// subtractive way, though, i.e. red+blue = purple.
// See https://en.wikipedia.org/wiki/Color_mixing

Color GetSubtractiveAverageColor(List<Color> colors)
{
  var invertedColorSum = Color.black;
  foreach (var color in colors)
  {
    invertedColorSum += Color.white - color;
  }

  return Color.white - invertedColorSum / colors.Count;
}