How to create small PDF files for the Internet

Question

I feel that PDF documents when intended to be uploaded on the Internet should be of minimal final size in bytes. Many strategies exist to create such small documents:

1. Pay attention to the size of the embedded raster images.

2. Create diagrams with tikz or pstricks and avoid external applications that can create unwanted big files. Using tikz or pstricks provides access to an almost unlimited control of the properties of a specific object. For instance, creating a point A of coordinates (1,1) should be preferred to a point A of coordinates (1.0000000,1.00000000), that you cannot control in many applications.

3. Pay attention to the fonts used in your documents. Some fonts contain a coding for a single size and are then scaled, when used in titles or equivalents. Some other fonts contain a coding for different size, making the document a bit larger. You may observe a non negligible difference.

I am interested in this 3rd point: have some of you investigated the best fonts for smaller PDF files?

Edit Compress.SmallPDF sounds like a good online solution to efficiently compress pdf files for free.

Answer 1

There are a number of tricks for getting optimized pdfs. Many of them are implemented in the tool pdfsizeopt. With some patches (posted in the pdfsizeopt bugtracker) this tool can run on all my tex-generated pdfs (and nearly all of the non-tex-generated ones). I use the commandline:

python ./pdfsizeopt.py --use-pngout=true --use-jbig2=true --use-multivalent=true --do-unify-fonts=false filetocompress.pdf

I use --do-unify-fonts=false even though it produces slightly larger pdfs, because of a bug where a few glyphs are not displayed with certain pdf viewers (windows adobe reader, for example).

There are indeed various things you can do during document production with tex, to make sure that the compressed pdf ends up as small as possible: several of these are discussed in the EuroTeX 2009 White paper about pdfsizeopt (available at https://github.com/pts/pdfsizeopt/releases/download/docs-v1/pts_pdfsizeopt2009.psom.pdf).

As regards fonts, pdfsizeopt will recode fonts to the very compressed CFF format, and take care of subsetting and duplication issues. I haven't investigated deeply, but in my tests it seems that of the 2 options for type 1 encoded T1 (multilingual) tex fonts, the Latin Modern fonts generally produce significantly larger PDFs than the CM-Super version (which is unfortunate, because Latin Modern is superior in just about every other way (see this question). I just did a quick experiment and this difference in size seems to be only for the pre-pdfsizeopt pdfs: after pdfsizeopt, Latin Modern is the same or smaller than CM-Super.

Using fonts that don't have optical scaling will indeed produce a smaller PDF, but I don't recommend it because if you are using multiple sizes then the non-optically scaled fonts will look much worse.

Answer 2

If for some reason you don't want to use pdfsizeopt: both XeTeX and LuaTeX typically generate smaller PDF files than pdfTeX because OpenType fonts are already encoded in either CFF or TrueType outlines.

Answer 3

There is the program pdfopt provided by Ghostscript which converts the PDF in the official web optimised format. This (quote from man pdfopt) puts the elements of the file into a more linear order and adds "hint" pointers, allowing Adobe's Acrobat(TM) products to display individual pages of the file more quickly when accessing the file through a network (unquote).

The usage is straigt forward:

pdfopt [ options ] input.pdf output.pdf

Just make sure that both PDF filenames are not the same. You might want to move output.pdf to input.pdf afterwards. This is what I do in my Makefile's for my LaTeX package prior to uploading them to CTAN.

Answer 4

(Not specifically font related)

A way to create smaller documents with pdf(La)TeX is to use

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

This will generally produce considerably smaller files but it requires pdf version 1.5 and might not be readable by old pdf-viewers.

Answer 5

Using true type fonts that are specified in the PDF standard (and thus available with every conforming pdf viewer) dramatically reduces for me the file size of PDFs generated with pdflatex. Else, other fonts are included in the generated PDF which increases the file size.

For example via

\usepackage{mathptmx}
\usepackage[scaled=.95]{helvet}
\usepackage{courier}

The scaling of helvet is needed, because it is by default a bit larger.

Note that the package times is obsolete.

Using common PostScript fonts with LaTeX describes these packages and more.

Edit To get a list of fonts the PDF standard 1.4 specifies see section 2.2.3 (page 36) and section 5.5.1 (page 339). To quote:

These fonts, or their font metrics and suitable substitution fonts, are guaranteed
to be available to the viewer application.

Section 9.6.2.2 of the PDF standard 1.7 uses a slightly other wording:

[..]These fonts, or their font metrics and suitable substitution fonts, shall be available
 to the conforming reader.

Thus for example, the acrobat reader on an (relatively) obscure Solaris system comes with some otf/pfb font files.

Answer 6

Give this a try:

#!/bin/bash
file=$1
filebase=$(basename $file .pdf)
gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dNOPAUSE -dQUIET -dBATCH -sOutputFile=${filebase}_verkleinert.pdf ${filebase}.pdf

Save it as a shell script and call it with

sh <shellscriptname>.sh <nameofyourpdffile>

Answer 7

I just open the PDF with Okular (any viewer should work) and then print to a PDF file. It looks exactly the same as the original, although it loses the hyperlinks. However, the savings is measureable. A 1.3 MB file drops to 80K ! There are no unused fonts or anything like that and the fonts aren't that big to begin with, so I don't know why the savings is no significant, but this should be the default output (with links - a link can't add but a few bytes).