One of the mainstays of Look-in from the early days, to the very finish was the double page colour pin up. In the 70's and 80's, this was nearly always accompanied by a feature either side of the posters.
Being an up to the minute entertainment magazine as well as a comic, music played a major role in Look-in throughout it's life, with it also having strips based on popular music acts of the moment, (Abba, Slik and Flintlock, etc...).
The pop posters beginnings are in 1972, before this the centre pages were used for large features, Survival utilising a lot of these, before being given over to Follyfoot for double sheet strips that read across the 2 pages, later Kung Fu had one or two of these too. So far as I am aware Issue 51 saw the first poster, featuring Marc Bolan, although the first in my collection is one of Roger Moore , with a feature introducing him as the new 007.
As glam rock hit big, there was a steady flow of groups like Sweet, Slade, Mud, Glitter Band, and their 'leader' Gary Glitter, long before the more infamous times he lives in now. There were the 'Heartthrobs' too like The Osmonds , David Cassidy and Michael Jackson.
The feature became known as the 'Pop Extra' for a while, and a strange thing was for Look-in to note on the cover of some issues, 'Free Pop Extra' as if to imply that the poster was a free gift. The poster was nearly always accompanied by a competition, usually to win the featured artist's new album, the competition invariably had a list of 5 questions, whose answers could all be found in the feature. Two annoying things about this is that when you buy Look-in's now, sometimes the pin-up is pulled out, and/or the competition slip is cut out, making a hole in the strip on the other side! It is something for collectors to note, especially if you haven't paid a decent price for an issue.
From time to time new movie or TV series would be featured, such as 'The New Avengers', or a large sports feature, such as the World Cup or Olympics.
During 1980, the poster spot, became an actual feature in it's own right, and was given a name - Colour Centre, giving indication to the fact that as well as the poster the feature was coloured too. You can see the title at the top of this page, which was at the corner of the actual pages. So far as I can tell The Undertones were the first artist to get the Colour Centre treatment in issue 23.
Colour Centre continued until the late 80's before just becoming a pop poster, not always with a feature, or sometimes more than one poster back to back, mimicking a lot of teenage mags of the time.