This filter provides sophisticated embossing effects, using Phong shading to simulate the appearance of light shining onto the image. You can use the input image as a texture map or as a bump map or both. You can also specify a separate bump map. In addition you can set the reflection characteristics of the surface (the diffuse and specular reflection coefficients and the specular highlight power), and the direction, color and intensity of the incident light. The picture shows two spotlights shining onto our test image.
Another example: Black text was drawn onto a white background, then the ShapeFilter was used to paint a gradient around the text. Finally, the LightFilter was used to emboss the result. Changing the shapeburst type can give different effects such as chiselled or round edges to the text.
Yet another example: The background is the output of PlasmaFilter, textured with LightFilter. The chiselled text is a bump map, prepared as above, using the ShapeFilter. This bump map was applied to the background with the LightFilter.
To produce metallic effects, you can increase the reflectivity of the surface and apply an environment map - an image from which the reflections are taken. In this example, the reflection map is simply an image filled with Perlin noise with the TextureFilter.
To make other types of metal, such as gold, just set the material color to yellow and the reflectivity down a little.
For this plastic text, add two lights, one pointing up, the other down and add a very small amount of a blurred version of the bump map as a glow.
The LightFilter can do more than this though. You can add multiple light sources of different types, such as spotlights and point lights. To find out more, have a look at Image Editor Tips - Embossing. I also have a Java animation of the LightFilter with a moving spotlight.