Older adults sometimes show a "positivity effect" in memory, remembering proportionally more positive information than younger adults. Using a modified Memory Characteristics Questionnaire, this study examined whether emotional valence impacts the phenomenological qualities of young and older adults' memories. Ageing did not impact the effect of valence on the qualities of high-arousal memories. However, ageing sometimes impacted subjective memory for details of low-arousal memories: In Experiment 2, older adults reported remembering more thoughts, feelings, and temporal order details about positive low-arousal stimuli, while young adults' ratings for those dimensions were higher for negative low-arousal stimuli. These findings suggest that valence most readily affects the qualities of young and older adults' emotional memories when those memories are low in arousal.