For the list of changes, please refer to the Revision history
For a number of years, the retroReveal website hosted by the University of Utah facilitated
"the collaborative discovery of hidden content in documents, manuscripts, music, and artefacts".
By separating an image into its component colour channels various transformations could be applied to reveal hidden elements in images that would otherwise be barely visible to the naked eye.
retroReveal found use by researchers in a number of fields and in particular, by philatelists, who found it especially helpful when trying to isolate postmarks and cancellations on stamps.
Unfortunately, however, the retroReveal website went offline in May 2022 and has yet to return.
ImageSleuth is intended as a free, cross-platform, standalone replacement for retroReveal. It provides forensic-style image processing based on the algorithms listed on the archived retroReveal Glossary page.
ImageSleuth is available for Windows, Mac or Linux and does not require an internet connection in order to function. Once it has been downloaded and installed, ImageSleuth can remain on one's computer indefinitely without relying on the availability of a third-party website.