The PDF’s formatting on page 39 likely employs:

To find a high-quality PDF:

Some low-quality scans have missing pages (especially the khatma or index of Qira’at). Always verify the page count matches the original print.

Scholarly archives and digital libraries provide various versions of these Mushafs for study:

: Many digital and physical copies use color schemes to distinguish between different rules of specific to each narrator. Digital Availability (PDF Resources)

: Many modern editions use specific colors to highlight where a word has different readings across the seven Imams.

Read one line according to Hafs, then re-read the same line according to Qalun (from Nafi’). The PDF allows side-by-side comparison without turning a page.