title: Afterimages from unseen stimuli.
abstract: Observers adapted to a field of randomly coloured twinkling tiles, in which was embedded a faint, subthreshold green letter. Observers failed to discern this letter, but they readily reported its pink afterimage afterwards. This demonstrates a storage of changing colours over time; adaptation occurs for the average of each retinal point.
authors.affiliation: Department of Psychology UC San Diego La Jolla CA 92093, USA; e-mail:  sanstis@ucsd.edu.
authors.forename: Stuart
authors.initials: S
authors.lastname: Anstis
authors.forename: Janos
authors.initials: J
authors.lastname: Geier
authors.forename: Mariann
authors.initials: M
authors.lastname: Hudak
keywords: afterimage; color vision; subthreshold summation; visual storage