I am studying orchestration and I wonder: Can anyone please tell me which notes are difficult to play on the trombone and why is that?

High D to FFF, they hard becuase they`re very very high.

Really, good notes aren`t hard to play, they are just hard to play well... if you can play the notes in the staff and they sound stunning, then, you can start to worry about pedals and triple notes, i really wouldnt worry until then, being a bass player, in orchestra i mean, i dont have to play much below or above the staff, i just make sure my tuning and pitch are amazing where they are.

Thanks a lot fo your replies

Anything from 4th E up is kind of hard to pull out with nice tune. but it all depends on playing I start loosing the sound around that point.