Thanks, folks! I agree, making mistakes is part of learning: it sure gets you to pay close attention. And learning is the most fun I have doing.

And thing were not even as educational as I thought, if the number of mistakes is my guide to judging education. I looked at the negatives on my light table today, and I can see clear detail in all of them, from shadows to highlights. Now, in one I somehow managed to pull the dark slide out again, halfway, after the exposure was made. I must have done it in pretty subdued light because there is still some of the image there on that half. In two, there were still light leaks, as well as, I see now vignetting caused by a filter. But these tow were shot with my 90mm Super Angulon, and there is at least 4x5 inches of perfectly fine image in the center of each frame, so those are halfway acceptable. And the two that I thought were underexposed? Well, I put one on my flatbed scanner, and with almost no adjustments, here's what it shows:

Click image for larger version.  Name: 4.jpg  Views: 46  Size: 209.1 KB  ID: 171118

So that's two more that will be okay.

(The weird thing is that the four that I thought were exposed most correctly need major adjusting before they look less than waaaaay over-exposed. This has to the scanner in my printer, which is not designed for photos at all, really, but it's all I have. On the light table, these negatives look lovely. I'm hardly an expert, but they look just like images in all of the several books I've bought and/or read on B&W photography in the last several months.)

And there's one more, which I thought was ruined because some of the emulsion scraped off as I removed it from the drum. It turns out that the small bit where that happened is on a patch of clear blue sky. A purist might call it cheating to fix that in processing, but that's fine by me. I'm willing to 'cheat' on a shot I may never get a chance to re-do.

So that takes me from what I thought were four usable images to seven, and two 4x5 'saves' out of a couple of 5x7s. I don't mind mistakes in the service of learning, but I like success better!