Again, if it were not fixed until developed then labs would often acquire copyright by default. what you're missing about this case is the location of the artistic authorship at the neus of intentionality, ie where the photographer chose and possibly arranged) the subjet, framed and lit, made decisions about exposure etc. By contrast, the best developer int he world can't express any opinion about the content of an undeveloped film until it has sat in a developer bath for some minimum length of time.

I certainly think there's an aesthetic dimension to the development of film. I've sat there waiting for an image to show up on a tintype as well as on more conventional substrates. However, the process of a development is fundamentally one of transcription (with all the possibilities for selective amplification/suppression) rather than one of authorship. If I hand you an undeveloped photograph of a landscape to process, not only will you not be able to turn it into a portrait, but you won't know what the content is until the development process is mostly complete; you are in the same sort of position as a recording engineer who can modulate the fidelity with which a musical performance is recorded to tape, but who does to thereby become an originator - s/he does not choose what is to be recorded, or perform that rendition of a composition, notwithstanding the skill involved in accurately transcribing the sound to tape.

ISTM that you're overly hung up on the 'expression' aspect to the point that you think authorship occurs at the moment of expressibility. I mention the tape analogy because an audio recording can not be perceived directly after fixation; you could wave a magnetometer over tape, stare at the grooves on a record, or view a printout of the waveform, but none of these would recreate the original acoustic information (although they would allow reconstruction of it). Acoustic expression only occurs when the recording is brought into proximity with a sensor and transducer - an apparatus of some kind. And whether the recording can be heard properly depends on the configuration of that apparatus - set the volume to high or too low and even the best recording will be rendered to a cacophony or a ghostly whisper. I suggest to you that the development stage of photography is no more than a chemical apparatus and the role of the lab technician is largely one of monitor rather than author.

While a skillful darkroom technician can take unexposed film and create new images from scratch by 'painting' on film and photopaper in the darkroom, and likewise can modify the content of exposed film using similar techniques, the possibility of creativity does not mean that all darkroom work is necessarily creative. Back to the case of these WW2 pictures, the darkroom technician's role is essentially one of discovery - the very absence of prior knowledge about the content precludes any sort of intentionality about the result, and intentionality is the essence of authorship.

>> Again, if it were not fixed until developed then labs would often acquire copyright by default. >>

Yes, if they were developing film creatively they would have some ownership. But, that is why the "publication" of the images by a film lab is done under the express direction of a photographer. There is a contract in force and terms agreed when you develop film using a service.

That is also how film labs avoid getting entangled in lawsuits, child porn, etc.

I am not so much hung up on 'expression' as copying / reproducibility. If it can't be duplicated or copied, or understood / perceived by audience copyright will not apply.

So undeveloped film is not subject to copyright.

Expression however does probably play a larger role in my thinking due to the copyright of binary software which is indeed absurd.

Thanks for helpful comments