Hi Dakar H,
I can undestand why you might be confused about this. However I think the short answer is that, with one proviso, you can go ahead and restore these images and publish them. And provided that you apply a certain amount of skill and creativity in doing the restoration - as seems likely from what you have said - then you will be able to claim copyright in the restored version of the images. The proviso is that if any of these plates could possibly be subject to Crown copyright, then different rules apply and in all probability they will still be covered by copyright. More on this later. I will proceed on the assumption that Crown copyright does not apply.
There are two approaches to why I think that the original copyright has now lapsed. The first is that the law which applied at the time these plates were made was the Copyright Act 1911.
Section 21 of that Act treated both published and unpublished photographs in the same way and the term of the copyright was 50 years from the date the negatives/plates were made. The subsequent legislation (the 1956 Copyright Act) did not change this situation for photograhs which were already in existence. From this you can see that the copyright in old photographs etc is not tied to the lifetime of the author, unlike with other types of work such as literary or musical ones. The 1956 Copyright Act did change this as far as 'new' photographs were concerned, which henceforward were treated the same as the other forms of copyright work, namely with a term of the lifetime of the author plus 50 years. This term was subsequently extended to 70 years in 1995, but none of that affects the plates which you own provided that they were made before 1 June 1957 (when the 1956 Act came into force).
This then leads to my second reason. One authority on copyright, Tim Padfield*, a former copyright advisor to the National Archives, maintains that section 12(3) of the Copyright Designs and Patents Act 1988 applies in the situation here and effectively reactivates copyright in
unpublished photographs even though it had lapsed under the 1911 and 1956 Acts.. But first, a word of caution about what follows: I need to talk about section 12 and paragraph 12 - these are two different things and are found in different places in the Copyright Designs and Patents Act 1988 (the current law). Here's what the relevant part of
section 12 says:
(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,
The following sections talk about what happens if the identity of the author subsequently becomes known, and what being made available to the public means. In the case of photographs, it means either publication or exhibition in public.
Mr Padfield and I disagree about whether this actually applies to photographs made before 1 June 1957. And the disagreement hinges on how to interpret 9 words in
Schedule 1, paragraph 12(2)(c) of the 1988 Act. This schedule sets out how the Act is to have effect retrospectively. Here's what the relevant parts of paragraph 12(2) say:
(2) Copyright in the following descriptions of work continues to subsist until the date on which it would have expired under the 1956 Act—
[...]
(c) published photographs and photographs taken before 1st June 1957;
I maintain that the part after the 'and' should be read as if it can stand alone. Mr Padfield maintains that the important part is the reference to published photographs, and therefore since unpublished photographs are not mentioned they are excluded from this provision and section 12(3) of the main part of the act therefore applies. Either way, the wording is very unclear.
However even if Mr Padfield is right and I am wrong on this, provided that photographs made from your plates were not exhibited or published after 1947 (ie 70 years ago), the plates are now out of copyright.
Sorry about the long and complicated explanation but it was necessary in order to provide you with the necessary certainty you need to proceed with the restoration.
I also mentioned that if you apply sufficient skill and creativity to the restoration you would be entitled to claim copyright in the restored versions. The authority for this statement lies in a case known as
Sawkins v Hyperion Records. Hopefully the Wikipedia entry explains what the case was about so I don't need to go into detail here. And even if it was deemed that there was insufficient skill and creativity involved to make your versions original in the copyright sense,
Regulation 16 of the Copyright and Related Rights Regulations 1996 (SI 1996/2967) would still entitle you to a publication right which is very similar to copyright but only lasts for 25 years from the date of publication of the restored works.
And finally I referred earlier to
Crown copyright. This applies to any work made by a servant of the Crown in the course of their duties. Servant of the crown has a wider meaning than just civil servants, and would include for instance members of the military forces and police. If, as we are assuming, your plates are unpublished, and you have any reason to suspect they may fall within Crown copyright due to their subject matter, the copyright term is 125 years from the end of the year they were made, and you would need to get permission from the
Director of the Office of Public Sector Information (now part of the National Archives) to publish them. I don't think this would be difficult, if Crown copyright does apply.
* Tim Padfield is the author of Copyright for Archivists and Records Managers. The reference is to paragraph 2.3.17 on page 50 of the 5th edition published in 2015.