It is known that visual working memory capacity is limited, but the nature of this limit remains a subject of controversy. Increasingly, two factors are thought to limit visual memory: an object-based limit associated with so-called "slots" models, and an information-based limit associated with resource models. Recently, Barton, Ester, and Awh (2009) introduced a measure of mnemonic resolution, which they dubbed "c". We show here that c is critically flawed, and cannot be interpreted as a measure of resolution. We recommend strongly against its use and interpretation, and suggest alternatives approaches for researchers who want to explore mnemonic resolution. (Contains 2 figures and 2 footnotes.)