General ⇒ pdflatex compression?

[rplantz]

I'm not sure where to ask this. I wrote a book using LaTeX and used pdflatex for the final product. I uploaded my file to Lulu so I could sell it (in pdf format) and they processed it. They produced a new file that I downloaded for proofing. I cannot see any visible differences in the displayed pages, but their file is 4.4MB, while the one I sent is only 2.2MB.

Does pdflatex do some compression? Has Lulu's system decompressed it? If so, did something get lost in the process?

I posted this question on the Lulu forum. A person on that forum who has been very good at answering other questions, answered this one with "I dunno." I can't imagine that they added 2.2MB of meta data.

[Stefan Kottwitz]

The change could be caused by a different font or font encoding, or by another way of compilation, such as LaTeX in dvi mode and dvips+ps2pdf instead of pdfLaTeX.

Check the document properties, and compare the embedded fonts. The Adobe Acrobat Reader can show you this, or pdffonts.

Furthermore, different pdfTeX versions can produce files with a different pdf standard and a different compression level, which can also be manually set, such as by

Code: Select all

\pdfminorversion=5
\pdfobjcompresslevel=3 
\pdfcompresslevel=9

Perhaps you have a pretty new version such as TeX Live 2010 or above, and Lulu compiled using an older version. In business, sometimes a stable version is used for a long time. Again, the Acrobat Reader and perhaps other readers too can show you the pdf producer and version.

Stefan

[rplantz]

Thank you, Stefan_K, your comments are very helpful. Exactly what I wanted to know. I'm using TeX Live 2012. I'll do further investigation on the files to see if I can figure out what's going on. As long as my buyers are happy, I guess it doesn't matter what Lulu does with my files.

BTW, I'm providing two versions of my book -- pdf for double-sided printing with appropriate margins (binding gutter, etc.) and pdf for ereading (uniform, small margins). LaTeX made it easy for me to adjust the paper size so that both versions have the same pagination. Thus an instructor using the book can refer to a page number, and it works for both versions. Another reason for providing the ereading version in pdf.

Bob