Published by the National Textile Center, June 2000
Comparison of PDF Normal with DjVu for Research Papers
This Resarch Briefs was published in June 2000 in paper form. It was then converted to PDF Normal with Acrobat Capture, suspects left as bitmap. To further optimize PDF filesize, the PDF file was "re-fried" using Acrobat Distiller. This produced an optimal PDF file with a size of 9.45 MB for 158 pages, or an average page size of 59.8 Kb.
Now we have converted this PDF file to a DjVu file. The size is reduced to just 4.2 MB for the 158 pages, or an average page size of only 26.6Kb.
The conversion of paper to PDF Normal using Acrobat Capture or comparable software will produce the optimimum smallest PDF filesize, but the formatting of the original document is slightly compromised by this "flavor" of PDF file. It works fine for this publication, however.
The DjVu format does not compromise the original format at all, and the superior compression methods produce a file that is only half the size of the smallest PDF.
Unfortunately for the DjVu format, the PDF format features an internal Bookmark contents index which is displayed in the initial view, and DjVu does not have an internal contents index. Fortunately, DjVu can produce the same table of contents hyperlinks and can also open to the index page 3 like the PDF version.
NEW! We have added to this comparison a PDF file that was processed with the CVision PDF Compression wizard. The bitonal photos and bitmap suspects are compressed with JBIG2 perceptually-lossless compression, and the grayscale and color photos are JPEG-compressed another 20%. The resulting PDF file is less than half the size!
In the table below, click on the size to open that file: