How to copy to folder: /System/Library/Filters? I am trying to create a new "reduced file size" export filter within preview. 

Therefore I copied the original file to desktop, made my changes and then I tried to copy back to the folder. This seems not to be permitted. Even with admin account and with sudo on terminal as well.

sudo cp Reduce\ File\ Size.114dpi.qfilter /System/Library/Filters
cp: /System/Library/Filters/Reduce File Size.114dpi.qfilter: Operation not permitted


How can I move this file to the folder?
User-created Filters should be saved to /Users/yourUserName/Library/Filters. You may need to create this subfolder if it's not already present in your user Library.

Also, note that the easy way to edit or create a new Filter is to use ColorSync Utility. If you edit the file in a text editor and get invalid XML, it can bring down the whole QuartzFilter system.