Analyzing the close-up

When we are talking about the potential range of meanings that can be assigned to a close-up, (and in particular the close-up of the face) what are the methods (if any) for understanding the significance of each of the key concepts Deleuze is making? Is it really possible to completely shed preconceived notions of the aesthetic implications of a close-up and replace them with new ideas for analysis? Deleuze argues that the juxtaposition of 'power and quality are intertwined and at any moment the two poles can pass from one to the next' (p.95).  If this is the case then what are the signifiers or clues for making this assessment? Furthermore what happens when we combine the analysis of two poles with a discussion of light and shadows? From what I gathered the face reflects light, retains emotion, and becomes intensive rather then reflexive. But can the effect of light and shadow really be reduced to that? I guess I am just looking for some clarification on how Deleuze reached these conclusions, and whether or not they hold up consistently, or only in these certain instances.