Notes on writing in one’s head vs. writing on the page with an extrapolation to subject matter

Utriusque cosmi maioris scilicet et minoris […] historia, tomus II (1619) by Robert Fludd
by Robert Fludd (1619)
These days it takes me a longer time to get started on the page with a poem. I spend weeks only thinking about lines. Used to, all that wheel spinning and doubling back took place on the page. What’s interesting is how that’s allowed for a shift in my subject matter: I’m more willing to give a little space to the intangible, the ineffable. So perhaps, for me, subject matter is tied more to the medium than I originally anticipated.

I wonder how it would change if I started writing only by hand . . .