"Di Gama" <di.### [at] gmailcom> wrote:
> I am working on a POV-Ray project which involves loading an external image
> and re-displaying it with no color adjustment. I recently discovered that
> "ambient 1" with no light_sources is not enough; the picture comes out
> brighter than the original. I traced the problem to the picture below. The
> top band is POV-Ray's rendering of a smooth gradient black to white at
> ambient 1 with no light_sources. The bottom band is an unmodified gradient
> black to white made by Fireworks. I hold in doubt neither gradient, and I
> think the problem lies in how the object color is transformed into a final
> pixel color. What is going on, and how can I disable or counter this
> change?

I tried setting assumed_gamma to everything under the sun, but I see
absolutely no change in the image. The help text on gamma was very
confusing. I am not using any special gamma additions, and I am viewing the
original and re-rendered pictures on the same monitor, so display gamma is
irrelevant. I am rendering to a BMP on a Windows. Here is the source for
the gradient picture:

global_settings { assumed_gamma 1 }
camera {
  direction .5*z
  right x
  up y
}
box {
  <0,-1,1>,<1,1,2>
  pigment {gradient x}
  finish {ambient 1}
  scale 1+x
  translate -x
}

This source is not shortened at all.

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