I duplicated the "Reduce File Size" Quartz filter, in order to set up one with higher resolution (never understood why the default filter has a resolution of a needle's tip), so I removed the "Image Sampling" options and kept only the "Image Compression" one.
However, seems like no matter what image compression setting I choose, the resulting PDF created with this filter is exactly the same.
Any ideas?
iMac 27″, macOS 12.7
When exporting a PDF and apply a Quartz filter to it, you can alter various settings, as per the attached image. So, I would expect that exporting a file as PDF and selecting the "Reduce File Size" filter would compress the included images as jpeg. Which seems like it is the deal, when using the default "Reduce File Size" filter. However, because I need a larger resolution file than the default, I duplicated the filter and completely removed the "Image Sampling" component from the filter. Now, it seems that the image compression setting does nothing.
Dependent upon the PDF content, it may use up to five different internal compression algorithms when the PDF is created. If the PDF content is at its maximum compression, redundant attempts at further compression will achieve nothing.
The PDF file I am trying to export using the filter is a two-page LZW-compressed TIFF file created by me. If I export the same file as jpeg with low quality, it definitely shrinks in size, plus gets pixelated, as expected. However, altering jpeg quality using the jpeg compression setting in the Quartz filter, does nothing. It should.
But as you mentioned, you are attempting to export that LZW compressed TIFF to a PDF, not another image format. You have no control over any of the internal PDF compression algorithms that may or may not be used on the source object based on its existing compression state.
Image Sampling changes do work; Compression changes do not. No matter what compression setting I choose, the output pdf is exactly the same.
Quartz Filter compression options don't seem to do anything
