Hi,
I hope someone has an easy solution for my problem.

I am trying to make some images for a description of the standard model of
particle physics, such as neutron, protons, quarks, electrons etc.

The images have to be combined and used in print. Apart from the previous
mentioned CMYK problem (do those colors turn ugly, yagh) I have a problem
with the background. I would like our illustrator to be able to cut out the
'solid' objects and place them in the desired color background. A good
contrast between the edges and the background helps to make the result
appear smooth.

OK, I know I can make all the background colors in POV-ray that I want, but
it is difficult to obtain the desired color in RGB as I can't predict what
it will be in CMYK, and the colors have to fit in the lay-out (colors of
other images, photographs etc.).

I thought I would render all objects with a white background. When the
background is blue or black, they look nice. However, when I choose a white
background, they suddenly appear to be very pale. Like a color slide film
that has received too much light. What is the best way to proceed? A problem
is that some objects, such as the trajectory of an electron, should be
transparent.

Should I instead of background use a plane (some shadows would be nice,
maybe), should I change the lights or other settings or is there another
possibility to obtain the desired result with a coloured background.

Looking forward to advise

Erick

Here follows an example of such a scene file, three quarks in a
'transparent' sphere


global_settings { assumed_gamma 2.2 }

#include "colors.inc"
#include "glass.inc"
#include "metals.inc"

camera{location <0,8,-20> look_at 0}
  background {color White}
light_source{<100,100,-100> White}
// create a point "spotlight" (conical directed) light source
light_source
{
  0*x                     // light's position (translated below)
  color rgb <1,.7,.7>       // light's color
  spotlight               // this kind of light source
  translate <40, 80, -40> // <x y z> position of light
  point_at <0, 0, 0>      // direction of spotlight
  radius 5                // hotspot (inner, in degrees)
  tightness 50            // tightness of falloff (1...100) lower is softer,
higher is tighter
  falloff 8               // intensity falloff radius (outer, in degrees)
}

#declare Media = media {
  emission 0.05
  intervals 5
  samples 1, 10
  confidence 0.9999
  variance 1/1000
  density {
    spherical
    ramp_wave
    turbulence 0.1
    color_map {
      [0.0 color rgbt <0, 0, 0,.99>]
      [0.1 color rgbt <1, 0, 0,.95>]
      [1.0 color rgbt <1, 1, 0,.9>]
    }
  }
}
sphere {<0 ,0,0>,.5 pigment {color rgb <1,.2,.2>} translate
<1.5,1.5,-1.5>no_shadow}
sphere {<0 ,0,0>,.5 pigment {color rgb <.2,.2,.7>} translate
<-1,-1.5,1.3>no_shadow}
sphere {<0 ,0,0>,.5 pigment {color rgb <.2,.2,.7>} translate
<0,.5,-1>no_shadow}
sphere { <0, 0, 0>, 5
  pigment { rgbt<1, 1, 1, 0.8> }
  finish {
    ambient 0.0
    diffuse 0.0
    phong 1.0
    phong_size 200
  }
  interior { ior 1.2 }
  hollow yes
}

sphere { 0, 1
  pigment { color rgbf<1, 1, 1, 1> }
  finish { ambient 0 diffuse 0 }
  interior { media { Media } }
  scale 5
  hollow
}

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