Just out of a screening of Joker, the new Warner Bros movie based on the character from the Batman comic books. And despite reports that the movie is not based on any actual comic books, that might not be entirely true.

Now Bob Kane, Bill Finger and Jerry Robinson, original writers and artists from those early nineteen thirties and nineteen forties comic books that saw the first appearances of The Joker get equal billing. But what about other comics creators?

There are four. Brian Bolland, J M DeMatteis, Keith Giffen and Irv Novick.

Novick drew a lot of comics over his sixty-odd year career, including a run in Batman with Frank Robbins – who does not get credited. He also was the artist for the launch of The Joker comic book with Dennis O'Neill – though Dennis does not get credited.

Bolland is best known in Batman-circles for drawing The Killing Joke, which established Joker as a failing standup comedian – though its writer Alan Moore is not credited. But then Moore has asked for his name to be taken off any adaptation of work-for-hire comics into other media.

And then Giffen and DeMatteis whose most famous Batman moment is 'One Punch', the scene in Justice League International where Batman knocks out Guy Gardner, Green Lantern, out cold with just one punch. It has been replicated many times since – and there are a couple of what may be seen as one punch scenes in the movie. Could their credit really be related to that?

There are two notable omissions; Frank Miller and Klaus Janson. There are a number of scenes that seem drawn from that comic book but there is one very specific scene that could not have happened without their work. It may be the most spot-on scene from the comics in the movie, but credit for it is there none…