colour-reversal

colour-reversal

or

color-reversal

n
(Photography) (modifier) (of film or photographic paper) designed to produce a positive image directly from a positive subject
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014