Q I was lucky to recover a damaged 12 MB PDF document from a print house, and now have it on a CD. I need to send this by email, but it is refused by Apple’s Mail application, as it is so large. I can reduce its size to 1.1 MB, but that renders it unreadable and unusable. Is there anything that I can do to squeeze it into a file small enough to email?

A This depends on the content of the document.

If it contains endless chapters of text, then they are going to be hard to compress any further, but a regular compression tool might be able to squeeze the whole document down a tad using Zip or a more modern method. However if the bulk of the file is in high-resolution images, you should not find it difficult to compress those sufficiently to be able to send it by email without rendering the images useless.

The original print house may be able to do this, or you could use a dedicated tool such as PDFCompress. Paid-for versions of Adobe Acrobat, such as the latest Acrobat 2015 DC, also include this as a standard feature, but are more costly and offer much more. If you have a Pro release of Acrobat, open the document and then use the Save as Other… entry in the File menu, for its Optimized PDF… command, tweaking the compression settings until you strike the right balance between file size and image quality.

Updated from the original, which was first published in MacUser volume 27 issue 15, 2011.