In recent years, PDF (Portable Document Format) has become a default distribution format for digital graded readers. Many educational publishers (e.g., Oxford Bookworms, Cambridge English Readers, Penguin Readers) offer PDF editions, often alongside ePUB or interactive e-books. However, PDFs are a distinct medium—neither purely print nor fully adaptive digital text. This paper asks: How do graded readers in PDF format support or hinder language learning compared to print or other digital formats?