External representations, including pictures, graphs, text, gestures, and utterances, are key components of all curricular materials in physics. Such representations play a key role in cognitive function, particularly insofar as individuals interpret the meanings of and apply meanings to these representations. We previously proposed a model of how individuals can make meaning of and with external representations through layered analogies and applied this model to learning abstract ideas in physics, i.e. EM waves. We extend this model in two ways. We distinguish individuals' interpretations of representations, which can be highly variable and fleeting, from the physics community's agreed upon interpretations, which are more stable and coherent.  We describe these two dimensions of representation use: abstraction based on the community consensus of concepts and salience based on readily accessible pieces of knowledge for an individual.