Henry ,

Consider the changes to your observation.  I think it might be incomplete
code rather than a bug:

#version 3.5;

global_settings {
        ambient_light 6
  assumed_gamma 1.0
}

// ----------------------------------------

camera {
  location  <0.0, +1.5, -4.0>
  direction 2.5*z
  right     x*4/3 //image_width/image_height
  look_at   <0.5, 0.5,  0.5>
}

background {
        rgb .7
}


// ----------------------------------------



box {
  -<0,0,0>-.0000001 //to pass the interpolation
  <1,1,1>+.0000001 //to pass the interpolation
texture {

material_map {
  sys "circular window 1 stupidly small.bmp" //
  map_type 0
  interpolate 2
  texture { pigment {colour rgb <0,0,0>} }     // Black
  texture { pigment {colour rgb <1,0,0>} }  // Red
  texture { pigment {colour rgb <1,1,0>} }    // Yellow
texture { pigment {colour rgb <0,0,1>} } //Blue
/*
  FROM POV-ray help on material maps......
"If particular index values are not used in an image then it may be
necessary to supply dummy textures.
 It may be necessary to use a paint program or other utility to examine the
map file's palette to determine how to arrange the texture list."
I believe this is why the strange behavior.
*/

texture { pigment {colour rgb <0,1,0>} } //dummy  these dummy pigments show
at high resolution
texture { pigment {colour rgb <0,0,0>} } //dummy   they should be black or
matching the bitmap pallette
texture { pigment {colour rgb <0,1,0>} } //dummy    to make the correct
effect.
texture { pigment {colour rgb <0,0,0>} } //dummy
texture { pigment {colour rgb <0,1,0>} } //dummy
texture { pigment {colour rgb <0,0,0>} } //dummy
texture { pigment {colour rgb <0,1,0>} } //dummy
texture { pigment {colour rgb <0,0,0>} } //dummy
texture { pigment {colour rgb <0,1,0>} } //dummy
texture { pigment {colour rgb <0,0,0>} } //dummy
texture { pigment {colour rgb <0,0,0>} } //dummy
texture { pigment {colour rgb <1,1,1>} } //index 15
} // material_map
}
rotate y*45     // To get a better look
}
//.......eof

Dean Johnson      another beginner......

Bush wrote:

> Apologies if this is known, I'm new to this.
>
> My scene contains a box with a material map on it (80x80x16 colours)
>
> When this scene is rendered several times, I get (seemingly random)
> different colours for the
> space outside the circle (which is palette index 15 and not specified in
> the map), and therefore the other two visible sides of the box. I've had
> black and yellow mostly (indices 0 and 2-15), but also red occasionally
> (index 1). And it doesn't make a difference what map_type is used.
>
> According to the docs, the colour should be 15%3=0 , so black. Have
> tested it with both BMP and PNG, with same results.
>
> I've posted the scene on binaries, it's only small.
>
> POV 3.5 Build 15, Athlon 650 o/c to 682, 512Mb RAM, Windows XP Pro.

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