Resolution cannot invent a lamp
Fill the frame with the page
If the sheet is a postage stamp in the photo, the PDF page is a postage stamp. Step closer. Parallel to the paper. Corners in the shot, then crop the rest.
Shadows at the binding
Books and stapled packs shade the gutter. Press the page flatter or shoot one leaf at a time. A contrast slider will not lift a black wedge into letters.
When “HD” is a lie
A 12 MP sensor already has more pixels than a clerk’s screen. Soft focus and motion are the enemy. We will not sell you a super-resolution fairy tale.