What
I noticed some unusual gestures that Karajan has when he conducts. The standard beat patterns use exclusively downward movement for downbeats. However, I recently watched quite a few live concerts on YouTube where Karajan uses upward hand movements to show important beats (including downbeats). I wonder if this is something that other conductors do and if so, why.
Clarifications
Before I link the examples I found, I want to clarify that I'm not focusing on whether Karajan beats time ahead of the orchestra. I know that it's a common thing, especially at those prolonged chords or the end of a phrase/section/movement (with or without fermata), where it's rare that an orchestra plays exactly "on the beat". I also know that conductors show dynamics/entrances/tempo changes BEFORE they happen. The unusual gestures I found happen when Karajan is perfectly on the beat. And they only happen occasionally (but stay steady and consistent when they happen).
Some Examples
Check the phrase that starts at 1:54. I see steady and clear upward movements on every beat. And it does not seem that he is half a beat ahead of the orchestra, because when he shows bowing gestures after the phrase repeats at 2:08, the beats are all at the bottom of his movements (this shows that he's always on beat unless he intentionally stops beating ahead of time, which is unlikely). The same happens again after the camera returns to him at 2:34. This is also a moment where trying to conduct using two directions on the beat really shows the difference. If I move from high to low on every beat, I have exactly the opposite movement to Karajan's at 2:34. But if I move from low to high, we're in sync.
This one is an even clearer example. Check the section that starts at 5:26. Every note is perfectly on time and at the moment when his gestures stop. Then he shows clear upward movements on every downbeat.
One more example is an early recording of Mariss Jansons who studied with Karajan. I believe he shows that conducting style most clearly. He stops doing that and uses conventional gestures during his later years but those early live concerts definitely show a similar style.
And as @Laurence mentioned, Frank Shipway. It shows a resounding similarity.
Hypothesis
Maybe it's just a way to show the phrasing. For example, if a conductor wants a big chord, they can hold their hands way above the head. Though it seems that it doesn't always apply to Karajan's case.
It could also be that he just decides to sometimes conduct half a beat ahead of orchestra, which I find hard to believe because it seems too sudden. It seems challenging to tell when that change happens even to a professional orchestra.
Another one that I think might be more likely is that it's just a way to show the downbeat. What textbooks say is nothing more than an accepted convention. The more important thing is to convey the messages to the orchestra. But I'm curious if there are other conductors that do this.