Compressing Pdfs on the Mac?

[MarjaE]

Some background:

I use a Mac and an older Kindle. I can't use touch devices.

I often have to process pdfs so they will open on the Kindle, or so that they will show once opened there. I also prefer to compress pdfs so they take less space and load faster. Sometimes compression is the only way to process them so they display.

So if it's important, or if it's one I've paid for, I keep the original pdf in another folder on my computer and the processed one in Calibre and export it as needed to the Kindle.

... But sometimes compression creates other problems. Apple's fixed some of the older problems, but also broken some of the processing solutions. And unfortunately compression still sometimes turns pages dark, making them unreadable.

Depending on the purpose, I use either PdfGenius (which is better at fixing pdfs which the Kindle can't open due to passwords, and better at compressing mixed text and images without blurring the text) and PdfToolkit+ (which is better at fixing pdfs where the Kindle can't display images). If necessary processing would expand the pdf, both apps refuse to expand it. But if I attach a large dummy page, PdfToolkit+ has been willing to process the combination, and then I can remove the dummy page.

Any other suggestions, especially for dark pages and for blanks instead of ligatures?

[willus]

MarjaE -- your post is somewhat confusing. You start out saying that you process PDFs so they can be opened on a kindle, and then you say that Apple has "fixed some of the older problems." How did Apple fix problems involved with displaying a PDF on a non-Apple device (the kindle)? Did you mean Amazon?

Also, depending on what kind of source PDF files you have, they could be re-factored in any number of different ways (convert to OCR, change compression type, etc.). Without knowing what type of source PDFs you are working with and without knowing what specific operations you are doing with PdfGenius or PdfToolKit+, it is difficult to respond to your post. If you want to increase your odds for getting help, maybe you could post an example of the source and the converted PDFs?

[MarjaE]

Apple used to delete Roman text layers at high compression and non-Roman ones at any compression, or if users added notes or bookmarks, or if users slipped with the mouse while reading them in Preview. That affected readability on *any* device, including the Mac.

The Kindle can't open "password encrypted" pdfs. PdfGenius has a security option to remove passwords.

The Kindle can't display some images from some other pdfs. That's especially annoying when it just displays blank pages, with a note at the bottom, instead of the original book's text. Pdf Toolkit+ and similar software can fix images by reformating the pages, which they do when compressing the pdf, but they refuse to do if it would expand the pdf. One trick to reformat the pages is to take a very large single-page file, which would compress from 50 mb to 500 kb, merge it with the other pdf, compress the combination, and then split the resulting pdf.