Standard lights in Poser provide both diffuse illumination and specular highlights. However, it is possible to create lights that only create specular highlights. Figure One shows a sphere lit by a single white infinite light.

Fig 1: Normal Light

Figure Two shows the same scene, but with a specular only light. The only part of the sphere that is now visible is that part lit up by the highlights. This is an extreme case, showing what happens when the only light in a scene is specular only.

Fig 2: Specular only light

Specular only lights are really simple to set up in the material room. Select the light you wish to modify, and change the diffuse colour to black. That light will now only create highlights.

Fig 3: Nodes for specular only lights