When I'm playing on a piano I can read which keys I should press and when. But there seems to be no indication how loud each sound should be in relation to another. Why?
It seems to me that this important information is lost and it's open to interpretation. As a result the music played can be very different from what the author intended because loudness is a whole dimension of expression. There would me much less interpretation if loudness was indicated at least relatively. I do so for my own purposes, I draw a rising and falling line over notes. Am I missing something?