Hi, I am having some problems processing 5x4 slide film. I am not attempting doing it myself, that would be ridiculous! No, I am using a lab to do that. The problem I am having is that my slides are suddenly coming back underexposed, by a huge amount, I would say 2 or 3 stops, and due to the low latitude for error with slide film, they are useless! I have done multiple tests, serviced my lens, even measured the time of its exposure using audio recording software (I am using a fairly slow and thus a readable shutter speed is possible). I dont know what else to do other than do more testing using black and white film, and comparing it to my other lens.

The question I would like to know is could the lab be messing them up somehow? I have not had any problems with them in the past, and my slides have always come back as I expected. I had though that with colour processing there is not a lot you could mess up, development times are the same for all films, as opposed to B/W film. If they did mess up would the slides come back underexposed, or would they not come back atoll?

If you can answer this then thank you, but I expect I will have to spend more money testing lenses! Thanks!