Letterforms, and the making of pages
A measure, a leading and a typeface walk into a column, and only one of them ever gets blamed. Paper and screen do not disagree about type — they disagree about light, distance, and how long anybody will sit still.
Two paper systems, one of them measuring a quantity that changes depending on what the paper is for. Here is the conversion table, and the honest reason it can never be exact for every sheet on it.
A palette is two decisions: what the ink is, and what it sits on. Everything else is adjustment, which is why one hex value can read warm on a cream page and dirty on a white one.