I've just discovered something that shouldn't have been a surprise at all: the "non-printable", "do not use these in inkjet or laser printers" transparencies that I bought actually do work for printing. At least, the one I printed looks good so far. It remains to be seen how well it actually shows up on an overhead projector, but I won't know that until tomorrow during my lesson.
When I first went looking for transparency sheets I expected that they'd just be one kind of all-purpose sheet, not one kind for laser printers and another for inkjets and another for both kinds of printers together (one kind on each side!) and yet another kind just for writing on! (How naive of me, you're all saying now. Any teacher should know that there are half a dozen different kinds!) I also expected that I'd be able to afford them. Oops! At $30 a box, I could only afford to pick up one box of transparencies and since they don't seem to come in a "writeable AND printable" variety (why not?!) I grabbed the writeable ones. I scribble on things more than I print anyway, right? Well, I needed to print out a topographical map for the contour maps lesson I'm teaching tomorrow and I realized I couldn't afford to spend $30 for the convenience of a single inkjet transparency (they come in boxes of 100, but I only need one). So, I did the typical cheap thing and went to see if my regular write-on transparency paper would suffice. It does.
The sources online told me that the ink would smear terribly, that it would dot up and not flow smoothly, and that it would turn my printer into an ink-dripping mess. Apparently the sources aren't familiar with our particular inkjet printer, because aside from a bit of dotting up which I can't see unless I squint, the transparency matches up perfectly with the paper version I printed. The borders and print are as clear as they're going to get, considering the map source (No offense to the USGS but most contour maps were not designed to be scanned and put online). I'm sure at some point I'll run into problems printing on "non-printable" transparency paper, but sometimes, it pays to think cheap.
Now if I could only figure out how to get my lesson plans written without wasting so much time, I'd be all set...