How are we to understand the phenomenology of imagining? Attempts to answer this question often invoke descriptors concerning the “vivacity” or “vividness” of our imaginative states. Not only are particular imaginings often phenomenologically compared and contrasted with other imaginings on grounds of how vivid they are, but such imaginings are also often compared and contrasted with perceptions and memories on similar grounds. Yet however natural it may be to use “vividness” and cognate terms in discussions of imagination, it does not take much reflection to see that these terms are ill understood. In this paper, I review both some relevant empirical literature as well as the philosophical literature attempt to get a handle on what it could mean, in an imaginative context, to talk of vividness. As I suggest, this notion ultimately proves to be so problematic as to be philosophically untenable.