Sort of, since the original PDF is image based, the size of the PDF is relatively big in order to display the clear pixels. After the PDF is OCR scanned, all PDF contents are text based. It shall reduce the file size dramatically.
Therefore, we have optimized the conversion process in a way that the PDF files are only 10% smaller than the original ones. But even so, these files are not as compressed as the original ones, but have a maximum size of about 300 pages. There's no other way to reduce size. At that time, the maximum size of a PGP message was about 500 pages. What's the point of it? Since I had published a book with this kind of files in the past, I have to admit that the files are very small compared to our expectations. It can be easy for me to convert them to PDFs using a program I'm familiar with, but I think if you relearning materials are going to be printed, you've got a better option: 3. Printout the PDF files. 3.1. Step 1 — Create a PDF file. Print all the files in the PDF folder, and save the resulting.