I really enjoyed this one, though it was way, way too easy, and the revealer (ALCHEMY) was a little straightforward and flat. It’s also kind of … ISH. I mean, you don’t “turn lead into gold” so much as allow lead and gold to occupy the same box—that’s more simultaneous existence than transformation. Also, if, as a solver, I am indeed changing one element into another, why am I changing lead into gold any more than I’m changing gold into lead. I guess the assumption is that Across comes first, Down second, but I definitely got AU first (with CAFE AU LAIT) and had to “change” it to PB to make sense of RAP BATTLE. So the revealer assumes a directionality (from this to that) that the solving experience doesn’t necessarily provide. And again, ALCHEMY is also not the most dynamic of revealers, in that I could tell very early on that there was an AU/PB thing going on. But … I’m also not sure what else the revealer could’ve been, and not every solver will be like me (sussing out the theme within the first minute or so, before ever hitting the revealer), so it’s fine. The revealer (ideally) gets you to the PB->AU gimmick, if you weren’t already there, and that’s all it really has to do. It doesn’t have to be flashy. The flash is in how the grid handles those rebus squares, and man does it handle them well. Earlier in the week we had a puzzle where the theme restrictions really worked against the quality of the theme answers, but today, the opposite somehow happens, in that we end up getting some real winners, like ROOFTOP BAR and PUSH-UP BRA and RAP BATTLE and MAKE A U-TURN, which, though I don’t love it as an answer, definitely “hides” the AU in the cleverest way, and makes me feel grateful that for once I’m seeing a U-TURN in a puzzle that isn’t a UEY (or, worse, a UIE—y’all went nuts in the comments yesterday over horrible TEC, which I have complained about in the past, possibly within the past week, but when you are talking about “Worst Fill Ever,” have some respect and remember that UIE exists). 

I did not know REB was a [Talmudic honorific], though having encountered REBBE in a Dell Crossword Puzzles book yesterday, I wasn’t caught totally off guard. This definition of REB allows you to bypass the whole Civil War angle, which I’m fine with (“Johnny REB is the national personification of the common soldier of the Confederacy” (wikipedia)). The trickiest square in the grid, for me—the one where I kinda held my breath and hoped it was right—was the “X” at PHX / LUX. For the most part, I don’t know the names of airports beyond some common three-letter codes, and the word “Harbor” in the clue for this one did not exactly scream “Phoenix!” (30D: Code for Sky Harbor Airport), so I had PHI in there at first. But LUI really seemed wrong for 42A: Illumination unit, so I pulled it and went with the “X”—LUX means “light” in Latin, so I figured that was the better guess, even though I had no idea LUX was a “unit” of any kind. I know the LUMEN and then I’m fresh out of light-related units, I think. No other significant struggles, though. As I say—too easy for a Thursday, but satisfying nonetheless. Great craftsmanship on display here. A nice variation on the Schrödinger puzzle theme type (where different letters are correct in both directions). Today’s the last teaching day of the semester, so it’s nice to have a puzzle to kick-start the good vibes! See you tomorrow.