Malcolm,
I've re-read your two posts , more attentively this time, and without contradicting John's more detailed advice and experience in such matters, would suggest that there are a couple of fundamental points to your situation.
Firstly, the contract. You had a verbal agreement, an ad hoc arrangement,
“ along the lines of "I'd like you to photograph this painting and do me two prints, please", usually in person or occasionally by email...”
“ Written instructions simply weren't necessary, and the work would no doubt have carried on indefinitely while she was still alive “
The terms of this agreement were known to you and your client. There was no disagreement between you and a harmonious working relationship continued until her demise.
What is not entirely clear is whether or not your ad hoc arrangement ever constituted (1) an offer and (2) an acceptance of the offer – both integral to a 'contractual relationship'. Given that you received some 'consideration' for your work it could be argued that the agreement constituted a contract.
But if so, what were her and your obligations under the contract ?
Were you paid in full 'up front' or or were you to be compensated on a pay-as-you-go basis ?
Was she obliged to give you an order for 100 prints or was it an understanding ?
Was the 'consideration' inclusive of the 100 prints or are you still owed monies for your 'original' work ?
And so on..
“ Clearly, it is open to either party in a contract to terminate that contract at some point, if it does not naturally expire .. “
Well, no - it's not. If indeed a contract existed then it's not open to either party to breach the contract without agreement from both sides. Unfortunately, your ad hoc agreement (or contract) did 'naturally expire'. But in the absence of any written agreement it is debatable whether or not her children inherited her contractual rights and obligations – I suspect not.
In the absence of any written agreement to the contrary, I believe that any judge reviewing this case would apply the law, as if no contract existed. And therefore three salient points would be:
(1) As you say, the IP issue and who owns the files
It has also been suggested, rightly or wrongly, that repro artwork photography is slightly different in that copyright in the actual photograph hinges on whether it is an exact copy or 'derivative work' as opposed to an original work in its own right. In the former case the photograph would be denied copyright protection, regardless of any skill or time spent in creating the image, whereas in the latter it would automatically acquire it. Hence the lack of clarity
(2) But, notwithstanding an unfavourable decision in (1) above - have you received full and fair compensation in accordance with your original agreement ?
(3) Additionally, under English law , you have what is referred to as the doctrine of reasonable expectations – a legal principle that the provisions of a contract are to be interpreted according to how a reasonable person (untrained in law) would interpret them.
Finally,
I would suggest that you do not continue any written communication, other than to state your position, for fear that it could, inadvertently, prejudice you in court proceedings. Should you need to write, make sure you mark each e-mail and letter with the heading 'WITHOUT PREJUDICE' . This will prevent them from using any of your letters and emails in court, should it come to that.
So, as suggested above, once you've taken professional advice, cross your arms and wait for a reasonable offer. If they wish to go to the expense of taking you to court – let them. You'll probably enjoy the experience of defending yourself ( I did) – and there's no-one better to convince the judge of your own sincerity.
Good luck (or should I say break a leg)!
Manoli
ps
Just remembered - there's an extremely likeable (and intelligent) solicitor on this site, kikashi, (posts quite often) - perhaps send him a pm and ask him if he'd be so kind as to give you a quick opinion on the thread ..
