The National Portrait Gallery in London currently has an exhibition "Glamour of the Gods", showing photographs of film stars from the 1920s to the 1960s. One of the displays shows a photograph before and after retouching. The label explains that retouching was meant to remove the effect of harsh lighting in accentuating blemishes. Thus the retouched photograph would give the viewer a fairer impression of what he or she would see, in ordinary light, on meeting the subject. Or perhaps, it would yield the photograph that would have been produced if high-resolution film could have been used in ordinary light.
These two are different, because only the latter respects the fact that one still has a photograph, and that seeing a photograph is not the same as seeing its subject in the flesh. We doubtless do some unconscious work on a photograph before our eyes, in order to imagine the experience of a meeting in the flesh. That makes the latter characterization better than the former, because it leaves a place for that unconscious work.
But it is still problematic. There is the obvious practical problem of limiting the extent of retouching. The difference made is astonishing, and one can assume that the photographer was happy to go way beyond correcting for the harsh studio light, in order to produce a false perfection. Beyond that, there is the theoretical problem of thinking in terms of a photograph that would have been produced if photographic technology had been different. The notion will only be well-defined if we can specify the respects in which it would have been different, and can justify our choice of one particular set of differences rather than any other set.
Conveniently, there may be a good answer here. We may assume either that the same film could have been used in much lower light because the subject could have kept perfectly still, or that the chemistry of film might have been different, so that fewer photons were required to produce a high-resolution image. But once we probe a bit, it seems that even those answers are not perfect. A human being who sets out to remain perfectly still for a minute will hold herself differently from one who is not required to do so. And there comes a point when fewer photons lead to blurred edges: a minimum number of photons is required for a given quality of image, regardless of the film's chemistry.
We should therefore ask whether we ought to make arbitrary assumptions in order to save an aesthetic analysis, on the ground that the assumptions look as though they are about something that is independent of the work of art: in this case, how people hold themselves, or the physics of light.