Despite a few tentative steps in that direction, colour was a long time coming to the British range and, when it did arrive, it was pretty disastrous. The colour plates were often out-of-allignment, rending pages difficult to decipher. Making things worse, the paper was often creased as well creating an immensely unattractive package.
Readers were also annoyed that the glossy centre spreads, introduced in 1981, were sacrificed for the new format.
Wisely, and possibly anticipating disaster, the Bullpen waited for the technology to bed down before rolling-out the process to established top sellers SPIDER-MAN and STAR WARS, although both switched for the summer.
The mighty Marvel Mandarins obviously also realised that the sums didn't quite add up as the number of colour interior pages also dropped after a few months, leaving issues a weird hybrid of colour, b&w +1 (a throwback to the earliest days of British Marvel) and plain ol' black & white.
The 1983 format change was the first of several changes which eventually led to the entire weekly range adopting the full-colour, 24-page glossy format by 1986.