Originally Posted By: Ira L
It is possible to compress a PDF in Preview. I have done it many times and the results vary in terms of savings and quality.

*In the Preview app on your Mac, open the PDF, then choose File > Export.

*Click the Quartz Filter pop-up menu, then choose Reduce File Size.

Remember that a scanned PDF file is an image just as a JPEG is an image. Image compression algorithms do their thing by discarding data. The variation in results are a function of the initial scan resolution (how much data you start with) and the compression level (how much of the original data is discarded in the compression process).


If we knew what it was we were doing, it wouldn't be called research, would it?

— Albert Einstein