How can I reduce PDF file size in Preview?

Question

Level 1

8 points

How can I reduce PDF file size in Preview?

Apple's Scan facility provided in System Preferences->Print and Scan is really quite good, and works better for me than the facility supplied with my Canon scanner, but the PDF files it creates are enormous and need to be reduced for use.

For some years now I have done this by editing the "Reduce File Size.qfilter" file in System->Library->Filter, replacing it with three similar files each of which provides a different degree of file size reduction. (I learned how to do this from a previous post.) This has worked very well indeed, though it is irritating to have to set it up again every time I upgrade my OS and even more irritating that Apple have never addressed the problem.

However el Capitan now prevents me from doing this even when logged in as Root User - I just get a 'No Entry' sign.

Is there a way for a relative technophobe like me to edit this file?

Or is there a better way to get manageable PDF file sizes from scans?

Thank you all for your help.

MacBook Pro (Retina, 13-inch, Late 2013), OS X El Capitan (10.11.3), Mid 2010 MacBook Pro

Posted on Feb 25, 2016 5:17 AM

Reply

Answer 1

norm123

Community Specialist

Feb 26, 2016 12:32 PM in response to kwagarratt

Hello kwagarratt,
I understand that you would like to compress some PDF's that you have scanned in. I know that you would like to keep this simple so I do have a few suggestions for the App Store. Using an app should help keep this simple as well as a streamlined process. I did a search for compress PDF and came up with a few apps that you may want to try. Some do cost money so make your best judgement by reading over the reviews.
PDF Compress Expert
https://itunes.apple.com/us/app/pdf-compress-expert/id646636356?mt=12
PDF Squeezer
https://itunes.apple.com/us/app/pdf-squeezer/id504700302?mt=12
PDFOptim : Compress, Reduce & Optimize PDF files
https://itunes.apple.com/us/app/pdfoptim-compress-reduce-optimize/id621276561?mt =12
Take care

Reply

Answer 2

K Shaffer

Level 8

36,106 points

Feb 26, 2016 2:37 PM in response to kwagarratt

Given how OS X has morphed over the last major upgrade versions, the easier

power-user settings, & choices available to even basic users have vanished...

Reduce the File Size of PDF document with Preview: (three years ago)

http://osxdaily.com/2013/12/12/reduce-pdf-file-size-preview-mac/

Some types of file reduction software may create artifacts and image distortion;

since they're not loss-less, depending on what they are, what they offer. And a

resulting file may actually be larger than the original, though reductions applied.

I've tried in Preview or other native OS X applications, also can lose quality.

Not sure if the ability to convert the file to another type, perform edits to size of

the actual content/image, then convert back is anywhere near possible now.

• How to reduce file size of scanned images in Preview: (make copy, first to test)

http://www.cnet.com/news/how-to-reduce-the-size-of-scanned-images-in-preview/

http://www.macworld.com/article/1168311/software/shrink-preview-files-without-ru ining-image-quality.html

Or not without a quality third-party software. Not sure about Graphic Converter.

Of course Adobe Acrobat (retail, not reader) was capable almost forever.

{I have a few older applications for Tiger 10.4.11 and Leopard 10.5.8 that can.

And aspects available in the older OS X versions, without additional software.}

Good luck! 🙂

Reply

Answer 3

kwagarratt Author

Level 1

8 points

Feb 27, 2016 1:52 AM in response to K Shaffer

Thank you, K Shaffer and norm123, for your replies. Both contributions are greatly valued.

The MacWorld article referenced by K Shaffer describes the system file modification that I have been using until changing to el Capitan, and which el Capitan now prevents me from editing in. It used to work well for me and I'd like to find a way of editing system files again so that I can reinstate it. My basic question therefore was whether it is now still possible for someone like me to edit system files in this way.

The cnet article about how PDFs are constructed was of great interest, but the processes described are far too clumsy to use everyday.

At present I'm using a web-based compressor <www.smallpdf.com> which seems to work quite well, but requires internet connection of course and can be slow with large files.

Obtaining a third-part compression program as suggested by norm123 is probably the way I shall have to go if I can't modify Preview any more. So far I've downloaded the free one and shall try it out. Again, though, this is an unnecessary additional complication in my view.

Preview is a really clever program, though it can be a bit iffy sometimes. I use it a lot for all sorts of things. It has a lot of scope for improvement though, such as with the compression of PDF files under discussion - the provided 'Reduce File Size' command is really quite useless. And it has also lost some useful functionality over its development which I miss badly - for example being able to add hyperlinks to PDF documents. I continually hope that Apple will pay it some attention again.

Best wishes to all.

Reply

Answer 4

kwagarratt Author

Level 1

8 points

Jan 3, 2017 3:55 AM in response to kwagarratt

Ah-Ha! I think I've cracked it - after nearly a year.

It was a comment I read somewhere about using Target Disk Mode with the new Macs which set me thinking, as it cautioned the user to be aware that it is possible to change System Files in a Mac from another Mac without intending to.

It is!

So I managed to borrow another Mac, connect mine to it as a Target Disk, and then modify my System files in the same way I always used to.
And it worked!

So now I can reduce my PDF file sizes to a variety of different extents by using a modified drop-down in the save window of Preview.

For info, my Mac is a 2010 model with Firewire800, but the Mac I used was a newer one with Thunderbolt. I had to buy a Thunderbolt-to-Firewire adaptor from Apple, which set me back two appendages, but it worked a treat. So Target Disk Mode is still available on newer Macs, Guys.

Oh; And the System File modifications? I have found two sets of options, but if you can't find them yourself I can probably work out how to attach them on this Forum.

Why on earth is Apple not doing this themselves??

Reply