Historic Book DjVu - PDF Comparision
This study compares a digital book titled "Historic London", in DjVu and PDF file formats.
This book is created with 600 dpi scanned images that were OCRed and placed in a PDF file. The book is 569 pages in length. The size of this PDF file is 66.78 MB, using the standard TIFF G4 compression in the PDF file.
The first rendition of this PDF file is a new version with the 600 dpi images downsampled to 300 dpi. The size of this reduced-image PDF file is 35.11 MB, almost half the size of the original with twice the resolution, as you would expect.
The next two renditions are compressed with the new JGIB-2 compression method supported by Acrobat 5. This compression method reduces the 600 dpi version to 70% of the size, and the 300 dpi version to an impressive size of 5.18 MB, which is only 8% of the size.
Two DjVu files were finally created with the images preserved at 600 dpi and at 300 dpi respectively. The 600 dpi version has a size of 20 MB, while the 300 dpi version has a size of 8.84 MB.
This 300 dpi DjVu file has a size which is just 13% of the original PDF size.
Compare the Results
Use the chart below to launch PDF and DjVu files.
Note that both PDF and DjVu files, page 1 displays while the additional pages download in the background.