A composer deals with music notation. There is always a balance between accuracy of notating ones musical ideas and the allowance for musicians to have self-expression through written music.
In notation composers have used different scales of volume. It started with a notation of loud and soft in the mannheim school with F and P, and has evolved to a system where we generally use 6 steps of volume - PP, P, MP, MF, F & FF - from really soft to really loud. But some composers, notably Tchaikovsky uses really soft as PPPP or more P's and really loud as FFFF or more F's. But Tchaikovsky's scale of dynamics can't be softer than really soft or louder than really loud. In the notation of six dynamics it goes from really soft to really loud, as does the scale of ten dynamics with four P's and up to four F's, so in interpreting volume in music one need to be aware of such things as if the composer notates for example ten different dynamics or six. An F would be softer in a scale of ten than a F in a scale of 6 dynamics. The more dynamics the more gradual the scale.
The more dynamics the more gradual the scale.