Dick Conley wrote:

> When rendering a transparent object using the following:
> rgbf<1.0, 0.0, 0.0, 1.0>
>  reflection { 0.17, 1.0 fresnel on  }
> conserve_energy
> with NO dispersion, I get a black image.

As a workaround, add a 0.01 green or blue to the colour.
Then it comes out red.

> Change the color to rgbf<0.0, 1.0, 0.0, 1.0> and I get a bright green image.
> Change the color to rgbf<0.0, 0.0, 1.0, 1.0> and I get a bright blue image.

> Here is my scene file:

For anyone wanting to investigate the bug, here's a shorter 
scene file demonstrating the problem.  This has two copies of an 
object, the one on the right having a small amount of blue added 
(producing a bright red patch that is lacking in the other 
copy).

#version 3.5;
global_settings { assumed_gamma 1 }

#declare Color1 = rgbf<1, 0, 0,    1>;
#declare Color2 = rgbf<1, 0, 0.01, 1>;

#declare It = mesh {
  triangle { <-7, 2, 3>, <-6, 3, 0>, <-4, 3, 4> } 
  triangle { <-9, 0, 0>, <-9, 0, 4>, <-3, -6, 0> } 
  finish {
    specular .8
    reflection { 0.17, 1.0 fresnel on }
    conserve_energy
  }
  interior { ior 2 }
}

camera { location <0, 22, 0> look_at 0 }
light_source { <0, 90, 0> color rgb 1 }

object {
  It
  pigment { Color1 }
  translate <-5,0,0>
}
object {
  It
  pigment { Color2 }
  rotate y*180
  translate <5,0,0>
}

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