I tried a new lab for my latest batch of E6. 5 rolls shot in 2 different cameras across several months... and they all came back with intermittent scratching on the base side. Argh! This is an expensive, professional, highly recommended E6 lab too. I like everything else about them - the processing was spot on, the slide mounts are smooth as silk in my scanner, the turnaround time was quick. But I just want to make sure it really was the lab. The scratches come and go (some slides have none) but when it's present, it's basically one scratch that wanders back and forth across a whole series of frames in a row, with little interruptions and dotted-line series of divots, followed by long continuous wavering lines. It's basically one long scratch, not multiple scratches, as if something were resting on the base side of the film as it was fed into the slide mounter? Not the perfectly straight scratch or parallel scratches you'd get from a problem with a camera pressure plate or cassette light trap.

Here's an example, with no ICE on the scan. ICE doesn't completely fix this, either :-( It's more horrific looking when magnifying the film as seen with a glare across it, but I don't have a good way to get a picture of that to show you.