Introduction to the scenery description langage of the POV-Ray Raytracer         - page 7 -
by Friedrich A. Lohmüller

VI. The Designing of the Surfaces
    - the texturing of objects

( coloration - (simulated) deformation - brightness and shining of the surfaces)

3.3. Texture = the quality of the surface of an geometric object. A texture basically has the following components:       3.3.1. The color and the transparency ("pigment")       3.3.2. The roughness of the surface ("normal")       3.3.3. The brightness and reflection quality ("finish")

Sample:

texture{ pigment{color Orange}
         normal { bumps 0.5 scale 0.05 }
         finish { diffuse 0.9 phong 1.0 } }

3.3.1.: Color (or colour) (must be defined!) and Transparency (only if necessary!)

These properties are defined by the "pigment{....}" statement.

Sample of color definitions:
As long as you have added the line on the top of scene text #include "colors.inc", you may use predefined colour expressions with English color names as an abbreviation: e.g.: pigment{color Red}
It's possible to define any kind of color you want by mixing red, green and blue light (additive mixing of colours!),
for this we use the statement for rgb-colors: pigment{color rgb<..,..,..>} (red,green,blue).
The numbers between the brackets are expressing the intensity of each component by float values between 0.000 und 1.000 . Where 1.000 = 100% and 0.000 = 0% of the according colour component.
Samples for rgb colors:

color rgb<0,0,0> = black (you may also write "color Black"), color rgb<0.5,0.5,0.5> = grey ("color Grey"), color rgb<1,1,1> = white ("color White"), color rgb<1,0,0> = red ("color Red"), color rgb<0,1,0> = green ("color Green"), color rgb<0,0,1> = blue,("color Blue"), color rgb<1,1,0> = yellow, ("color Yellow"), color rgb<1,0,1> = a greenish light blue called cyan, color rgb<1,0,1> = a violetish red called magenta. color rgb<1,0.65,0> = a warm orange yellow, color rgb<0.25,1,0> = a yellowish green ("color YellowGreen"), color rgb<1,0,0.25> = a violetisch red. Further more we can dim and brighten colors: color rgb<1,0.5,0.5>= light red color rgb<0.5,0,0> = dark red, etc. etc. ..... It will be a good idea to take some simple spheres and to try it out by yourself! Human eyes can see about 16 million different colors!!

The statement "pigment{...}" can be used as stand alone statement (without being inserted in a "texture{...}" statement), but: see my remarks about the "finish" statement!
Behind the statement
#include "textures.inc"
you may use all predefined color patterns (pigments) and textures as ready-mades.
Sample:

 texture{ pigment{Jade}
         finish{ diffuse 0.9 phong 1.0}}

Other predefined pigments are e.g.: Candy_Cane, Red_Marble, Brown_Agate.
Sample:

texture{Cork
        pigment{ quick_color Tan}
        finish { diffuse 0.9 phong 1.0}}

Other predefined textures are e.g.: Polished_Chrome, Polished_Brass, Green_Glass .

3.2.2.: The Roughness of the Surface (optional!) This is defined by: "normal {.....} ".)

This is an optional texture statement! If the roughness is not defined the surface will appear smooth.
Here are some of interesting effects, which can be defined by the normal statement: bumps, waves, dents, ripples, wrinkles.
If you try it out and the effect seems to fail (no change to see!) so in most cases this will be because e.g. the bumps do only one bump on a square of 1 x 1. If you scale it down e.g. by "normal {bumps 1 scale 0.05}" or something like that, this problem mostly will be solved.
It is important to know, that all these deformation defined by "normal { ... } are only simulated surface deformations by a more or less rhythmic tilting of the surface normal. But because it is only used to calculate the reflections, this does not really deform the shape of the geometric object. So the silhouette of these objects will stay totally smooth. As a consequence of this, the deformation of the surface by this method is limited to those cases, where this not deformed outline of a bumpy object does not spoil. In those cases we can design very fascinating realistic surfaces by this simple (and mostly very fast) trick.

3.3.3.: The brightness and the Reflection (should be defined!) This is defined by "finish {....}".

The most important values are:
(Assuming to use the statement "global_settings {assumed_gamma 1.0 }" at the top of your text!)
ambient 0.10 This is the brightness of indirect illuminated surface parts (should be defined!)
(This simulates only the effect of indirect illumination, to calculate it a little bit more correctly we can simulate it by the so-called ":radiosity": - a totally correct calculation of it is nearly impossible!)
diffuse 0.90 This is the part of the brightness of the surface which is caused by the directly hitting illumination!
reflection 0.15 This is the reflection component of the light we see coming from an object to our eyes (camera).
phong 1.0 A simple form of simulating highlights on a surface

!!! Remark:

The POV-Ray defaults are: (Version 3.5, 3.6): "finish { ambient 0.1 diffuse 0.6 }". On computers with Intel's (486, Pentium etc.) in this way the colors appear much too dark! It's recommended on these systems to increase these values up to "finish {ambient 0.10 diffuse 0.9}".
I can highly recommend to fix the values of diffuse and ambient in general way bx the instruction

 #default{ finish{ ambient 0.1 diffuse 0.9 }} 

at the beginning of a scenery description and change these values only for e.g reflecting surfaces.
If you want an object to appear with more contrast between dark parts (deeper shadows) and shining parts so you should keep in mind that the sum of ambient, diffuse and reflection should be 1 = 100 % for realistic viewing. So while decreasing ambient we should increase diffuse e.g. "finish {ambient 0.05 diffuse 0.95}".