Change lighting in ChromaticityPlot3D

Question

It looks to me like ChromaticityPlot3D has some default lighting, but unlike most Graphics3D functions the Lighting option doesn't seem to have any effect.

However, the documentation states "ChromaticityPlot3D accepts all Graphics3D options with the following additions and changes: ...".

Any ideas how to affect the lighting? Is it possible to produce a Graphics3D object from the chromaticity plot? I am trying to achieve unshaded lighting like Lighting -> {{"Ambient", White}}.

Answer 1

If you look at the InputForm of ChromaticityPlot3D[{"WideGamutRGB", "sRGB"}] you'll find several spots where it says Lighting -> "Neutral"

So if you want to change that, you'll have to modify the output of ChromaticityPlot3D using a replacement rule. Here is an extreme example, one that totally ruins the plot but shows how to change the lighting,

ChromaticityPlot3D["WideGamutRGB"] /. 
   Rule[Lighting, "Neutral"] :> Rule[Lighting, #] & /@ {"Neutral", 
  None, {{"Ambient", White}}}

Answer 2

One could override the setting for each polygon group (or GraphicsGroup[]):

cp /. p_Polygon :> {Lighting -> {{"Ambient", White}}, p}
cp /. gg_GraphicsGroup :> {Lighting -> {{"Ambient", White}}, gg}

---

Update: Addendum.

While Lighting shows up in Options@ChromaticityPlot3D, it is not listed among the options in the docs for ChromaticityPlot3D. However, it inherits the setting for Lighting from ParametricPlot3D before it is embedded as styling in the graphics primitives: If the setting is not Automatic, then ChromaticityPlot3D won't override it.

With[{opts = Options[ParametricPlot3D]},
 Internal`WithLocalSettings[
  SetOptions[ParametricPlot3D, Lighting -> {{"Ambient", White}}],
  ChromaticityPlot3D[{"WideGamutRGB", "sRGB"}],
  SetOptions[ParametricPlot3D, opts]
  ]
 ]
(* same plot as above *)

See this answer or this one for more on Internal`WithLocalSettings. In this case one might simply handle things oneself as follows:

  SetOptions[ParametricPlot3D, Lighting -> {{"Ambient", White}}];
  ChromaticityPlot3D[{"WideGamutRGB", "sRGB"}]
  SetOptions[ParametricPlot3D, Lighting -> Automatic];