film processing

Today I got my class to divide into group, spend an hour shooting rolls of 16mm film, then I took them to the darkroom and workshopped them on hand processing. The first two rolls worked perfectly. Then after we brought the second set of rolls in from the outside where they were being exposed to sunlight to reverse them to a positive image, I was momentarily distracted when one of the students asked, from behind me, "is this the developer". I turned to see that he's put the film back into the bleach. "NO!!!" was my reply. It was in the bleach about 15 seconds before we got it into water then into the correct developer. The image seemed intact, although I warned him that the blacks might be gray. Too much longer in the bleach at that point and the film would have been clear. The actual result, visible only once we got it on the screen, was that the blacks shimmered and crackled while the whites and grays looked fine. Amazing.