I've recently dug out my old SLR camera again. I've just got the prints and scans back from a reputable high-street company and I'm not very impressed with the results.
There's a big vertical scratch in the negative on the right side of this crop and also some small blotches in the top left corner. The scratch on the right of the image is a scratch on the negative itself and corresponds exactly with a dip in the edge of the negative. I can't make out the blobs on the negative though, although they may be too small for my eyes! There are other similar examples on both this film and other films from the same batch.
My suspicion is that somebody or something in the lab did a hatchet job on the negatives whilst cutting them and the negatives were still wet whilst scanning and printing. I don't see how it could be my camera body, or dirt causing it given the direction of the marks in relation to the film. The example image is from the middle of the roll too, so not something I could have done whilst loading the film.
I'd appreciate some input though to check I'm not being an idiot before complaining; is my view a fair assessment? Is it likely to be just a shoddy processing service?