I work a lot with 2-bit (black/white) files of music scores. Since there is not a lot of text, the OCR-based deskew doesn't always work. In the current version of Acrobat DC there is NO incremental rotate, and if you use the "Edit Using" function to get to Photoshop, the Arbitrary rotation functionality is unavailable. This means there is CURRENTLY NO WAY TO DESKEW MUSIC using any combination of Adobe products. This is a bug that needs to be fixed.