Highlighting and Shading

Needless to say, miniatures of the type that I paint - namely 28 mm scale - are quite small.  In fact, if you guessed that they were 28 mm tall, you wouldn't be too far from the truth.  

This small size means that miniatures do not cast much of a shadow on themselves, the way objects in full-scale reality do.  Take a look at your own clothing, and you'll notice that the folds and crevices in the cloth appear darker, while the "peaks" of the folds appear lighter.  Leather clothing, in particular, demonstrates this very well.     Much of what we see is interpreted in three dimensions because this is our brain's interpretation of varying amounts of light and dark.  

Miniatures are too tiny to show much in the way of varying amounts of light and dark.  This is why the highlights and shadows need to be actually painted onto the miniature.  A miniature with no highlighting or shading tends to look rather flat, and poorly defined.  By adding highlights and shadows, we are enhancing the models three-dimensionality, but we are also exaggerating the detail, so it can be more easily seen.

A rudimentary way of adding highlighting and shading to a model is to paint the entire model with "base" colours (essentially these are the "mid tones"), then adding a wash of a darker colour, and drybrushing on highlights.  This essentially gives three "steps" (or stages or tones or shades etc) of [usually] the same colour.