Copyright is all about the creative work, be it literature, music, drama or artistic (which includes photography, and has very little to do with any products on which the images appear. So on that basis, the images you want to reproduce may well still be in copyright because the authors (the photographers or graphic artists) could still be alive, or more probably, will have only died within the last 70 years. Only where the author died before 1942 can you be reasonably sure that copyright no longer exists and you are free to reproduce the image.
Ths biggest obstacle you face is finding these details about the photographers or artists. And if you are seeking to licence use of images where you are sure the work is still in copyright, the next biggest hurdle is tracking down the current owners of the copyright. In many cases the copyright will have been owned by the company which published the postcard etc, but the term is still based on the life + 70 years of the employee who produced the work. Most of these companies will have ceased trading, or been taken over by other companies many years ago.
In either case, using the many websites dedicated to collecting old postcards, and museums such as the V&A and the British Library, may well be of help in your quest.
As the law currently stands, if after exhaustive research, you still cannot establish the identity of the author of a particular work, then Section 12(3) of the Copyright Designs and Patents Act 1988 can be applied:
(3) If the work is of unknown authorship, copyright expires—
- (a) at the end of the period of 70 years from the end of the calendar year in which the work was made, or
(b) if during that period the work is made available to the public, at the end of the period of 70 years from the end of the calendar year in which it is first so made available,
So even with this provision, some of your World War 2 material and the magazines from the 1950s would not yet be in the public domain.