This paper considers two explanations for negative color afterimages: that they are the result of overstimulation of the retina, or that they are a result of training and are part of an innate memory that begins in the retina. Moreover, the innate memory hypothesis comes with an additional speculation that innate memories are part of a mirror universe and have a panpsychist origin. By measuring the duration in one person’s experience it was found that a 40-second exposure to blue comes with a yellow afterimage that lasted 35 seconds. This was only 4 seconds longer than the afterimage that followed eight 5-second showings of blue that were separated by seven 5-second refractory periods that showed white light. That is, the skimpy 4 seconds did not impress given the claim that overstimulation causes afterimages and given the whopping 35 seconds (7×5) of refractory time allotted to the alternative. Because the seven refractory periods also came with afterimages, the cumulative duration of afterimages was actually 66 seconds and this provides a stronger contradiction of the explanation based on overstimulation. Furthermore, a 5-second showing of blue generated a 10-second afterimage, a 200% increase over the showing of blue. However, with more stimulation the 40-second showing of blue generated an afterimage that was only 87.5% as long as the stimulation time. Taken together, these demonstrations marginally support the memory explanation, but there remains room to disagree.