Two Diet Plans for Fat PDF

As Adobe's Portable Document Format has exploded in popularity so too has the number PDF generators, and predictably the quality of generated PDF varies considerably. This paper surveys a range of PDF optimizations for space, and reports the results of a tool that can postprocess existing PDFs to reduce file sizes by 20 to 70 % for large classes of PDFs. (Further reduction can often be obtained by recoding images to lower resolutions or with newer compression methods such as JBIG2 or JPEG2000, but those operations are independent of PDF per se and not a component of the results reported here.) A new PDF storage format called "Compact PDF " is introduced that achieves for many classes of PDF an additional reduction of 30 to 60 % beyond what is possible in the latest PDF specification (version 1.5, corresponding to Acrobat 6); for example, the PDF 1.5 Reference manual shrinks from 12.2MB down to 4.2MB. The changes required by Compact PDF to the PDF specification and to PDF readers are easily understood and straightforward to implement. Categories and Subject Descriptors E.3 [Coding and Information Theory]: Data compaction and compressio