How to get my Mac (High Sierra) to recognize custom Quartz filters I created to reduce file size?

Solution 1:

I have had success on macOS High Sierra 10.13.4 with putting Quartz filters in a Filters folder within my user's Library folder:

/Users/my_user_name/Library/Filters/

in other words:

Macintosh HD > Users > my_user_name > Library > Filters

However, your Library folder is normally hidden. An easy way to navigate to it is to click on the Go menu in Finder and while the menu is down hold the Option key. Library will then appear in the list. Once you open it you can create the Filters folder which probably doesn't exist, and put your filters there.

For reference, the filters I am using are those that Josh Carr posted to GitHub.

Solution 2:

If the Quartz Filter is not correctly written (it's an XML file), then it will not load. The ColorSync Utility should show you all the installed Filters on the system. You can also create and edit them here.

As you say, Filters will be loaded from any "Filters" subfolder of the User or root-level Library. (Also the /System/Library/Filters folder, now protected by SIP.) This has not changed in any version of MacOS.

Filters can be placed in the PDF Services subfolder of the Libraries, and then will appear in the PDF button of the print menu. If selected, a PDF will be saved to the Desktop with the Filter applied.

There was a bug in early versions of High Sierra in which filters would not always be applied to certain PDFs, but it has been fixed by Mojave, if not earlier.

Solution 3:

In Catalina (and probably earlier) you can also use the ColorSyncUtility that comes with MacOS and add new filters under "Filters".

If you just want to adjust an existing filter, right click on the filter you want to change and select duplicate. Now you can change the values as you wish. You also have the option to create a whole bunch of new filters.