The last tutorial (112) explained how high, mid and low value ranges can be applied to give us some options for mood and story.
This tutorial goes a bit further. We can play with accents to add a bit or interest.
High Key Major:
In general, the key is high range, except we are choosing to add low accents to bring interest and make some areas pop.
Mid Key Minor:
In general, the key is mid range, except we are choosing to add low and high accents to bring interest and make some areas pop.
Low Key Major:
In general, the key is low range, except we are choosing to add high accents to bring interest and make some areas pop.
Those are the 6 value options available to us. Though each option can have many multiple varieties depending on the complexity of the image.