Close
Wikipedia describes this as "illuminant metameric failure". Images that look the same under some lighting (eg. halogen) may look different under other lighting (eg. the LCD light inside your scanner).

http://www.normankoren.com/color_management_3.html talks about one cause of this, which I suspect is the issue here:

spoiler
http://qualityinprint.blogspot.com/2009/03/issues-of-optical-brightening-agents-in.html talks about another: OBAs, which make a print look bluer under a light source containing UV. This is common in newspapers, apparently, and can be detected with a blacklight.