A section mate was using 1-3 fingering for a long count high 'F' concert instead of open or 4th valve. We were terribly out of tune. I added the 4th valve and it seemed worse. I noticed my section mate was using 1-3 fingering. I asked him about it (he plays a YEP-642) and he said he thought it was better in tune. It wasn't, but way too sharp. (I think maybe he used to use 1-3 on his old 'bent bell' Conn years ago). I told him since 1-3 is often used to lower the high 'Eb', that the high 'F' is risky. Told him it's probably 12th or 13th partial. But... I couldn't figure out which partial that would be. Playing the high 'Eb' would be 5th partial I think. What partial would 1-3 be for high 'F' be? Or... is it considered a false tone?
There's a real exposed section for the euphs in Dvorak's "Finale from the New World Symphony". Since it's marked 'pp' we decided that just one euph would play that part. It's a two octave run from low 'F' to high 'F' 3 meas before rehearsal 3 if you're familiar).