When documents are scanned as single page images, and then put together into a single PDF file, they can become quite large in size. This is certainly true if you set your scanner’s DPI setting too high, or if there are a lot of color photos in the scans. FamilySearch takes PDF files up to 15 mb in size. What can you do if your PDF file is larger than that?
There are PDF apps that can shrink a larger PDF to a smaller size. They will do so at the expense of quality. The larger the “shrink”, the lesser the output quality. At some point, you may just need to split your PDF file into smaller collections.
The BEST WAY to avoid large PDF files is to avoid scanning your documents or images at a high DPI setting. This is not an uncommon problem when patrons visit our local FamilySearch Center. If you are scanning above 300 DPI and plan to combine those scans into a PDF, you will run the risk of a LARGE PDF.
In most cases, if you have a bunch of large PDFs, I would recommend purchasing a good PDF editing app. There are a fair number of them out there for both Macs and PCs. Adobe Acrobat is the most well known, but can be pricey to use. Web search for PDF apps that can create and edit PDF files for purchase. Windows 11 App Store will also have some PDF apps, but read the reviews before purchasing them. You do not need any fancy features. For Mac users, the Preview app can assemble multiple images into a single PDF file, compress your PDF, and do markup, and it is FREE.
There are also free online PDF apps, however not all of them are safe to use. In March 2025, the FBI put out a bulletin warning the public of significant scamming issues with online converters. The online site will convert/shrink your PDF file, but in the process downloads maliscious software onto your computer. I can only imagine this problem to become worse with time.
