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Controlling values is important to create the illusion of realism in a painting. Under the same lighting circumstances a metal object reflects light differently than a piece of cloth. Understanding how this translates into values is important to express the difference in textures.
Having no control over your values can cause a painting to fall apart, or lose all sense of depth. In this illustration I did a little experiment. I used my values in an unconventional way, by deviding my illustration into four sections, and apply a different range of values to each section. Within each section, the relative use of values is as usual. The range was set in advance.
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I used the posterise filter, to show how I four basic values for the entire illustration: black, dark grey, light grey and white. When I block in the basic values for an illustration I trie not to go into detail, but stick to only a few basic values. Refinement and detailing come later on.
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The use of values this way, gives an unnatural look to the whole of the image. It's as if the different artists have been cut out an put together as a collage. I magnified this effect by reversing the laws of pespective in some areas. Big shapes in the back, small shapes in front.
Setting a limit for the use of values this way is a great exercise to understand and control values. It made me realize what the effect is and made me use values in my other paintings more
consciously.