Flipping through the booklet that comes with the 50th anniversary edition of The Beatles’ Sgt. Pepper’s Lonely Hearts Club Band, I fell a little in love with this photo of McCartney re-positioning a microphone. I’ve cropped and zoomed him in the image above, but here he is in context:

The others are all at their posts. George at the organ. John in front of an amp. Ringo drumming. But there’s Paul, up on his feet moving a microphone. Why isn’t an engineer doing it for him?

In Geoff Emerick’s memoir, Here, There, and Everywhere, he writes about all the strict rules and restrictions of the recording studio in that era. (When the Beatles first started out, the engineers were still wearing lab coats.) They broke all sorts of rules and protocol for the albums leading up to Pepper’s, and, clearly, the rules had mostly been thrown out the window at this point. Emerick writes that Paul was the most curious of the crew about the recording process. He wanted to get hands-on, which is what he’s doing in this photo: He’s not waiting for some engineer to fix the sound.

Paul would also stay at the studio late after the other band members had gone home to overdub his bass lines one section of the time, getting them as perfect as he could. “There were nights when he would labor until dawn,” Emerick writes, “keeping at it until his fingers were literally bleeding.”

Paul was never my favorite Beatle, and Sgt. Pepper’s has never been my favorite album. (Too much of what John Lennon called “Paul’s granny music” for me.) But looking at this picture and hearing those huge, sweet bass lines on the remix, I admire him more and more. He was working. Moving his own damned microphone.