TeX - LaTeX Stack Exchange is a question and answer site for users of TeX, LaTeX, ConTeXt, and related typesetting systems. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Consider this sample code:



When I compile this with latex and then use dvipdfm, the output file is 7893 bytes. When I use pdflatex, the output PDF is a whopping 20696 bytes. Naturally, the outputs are visually indistinguishable one from another.

Why does this happen? What does pdflatex put in there that takes so much space?

For reference, I have used the latest MikTeX 2.9 on Windows 7, and ran the commands without any extra switches.

share|improve this question
pdflatex generates "verbose" PDFs; the results are probably similar if you (lossless) compress the PDF afterwards as described in tex.stackexchange.com/q/18987/3751. – Daniel Dec 13 '11 at 15:28
@Daniel: Yeah, when I ran ghostscript on the PDF from pdflatex, I got pretty much the same size as the other one. Still, that doesn't answer the why part of the question. – Martin Tapankov Dec 13 '11 at 15:35
Could it be because dvipdfm processes an already processed version of a file (.dvi), while pdflatex processes a file from scratch (.tex). As such, there could be additional (unused) information contained within when processing it with the latter, while the former could selectively include only "the necessary components." – Werner Dec 13 '11 at 16:52
pdflatex embeds the font in type 1 format and dvipdfmx embeds the font in type 1c format. I think the latter compresses better, but I cannot find a reference to back the claim up. Use pdffonts <pdf-file> to see the difference in embedded fonttypes. – Martin Heller Dec 14 '11 at 21:42
up vote 22 down vote accepted

Martin Heller has stated the correct answer: dvipdfm uses a different font format than pdftex. You can look into the PDF file by loading it into a text editor. Sometimes (well, often), the objects are compressed and you only see some data. So you either need a decompression algorithm built into your head, or use a tool like qpdf to uncompress the objects (that is what I do):

qpdf --qdf --object-streams=disable test-pdflatex.pdf test-pdflatex-long.pdf

Now the output file is much more readable and you can now compare the output of dvipdfm and pdftex. I don't know if this applies to all cases, but in this example you can take a look at the font object:

% dvipdfm:
9 0 obj
  /FontFile3 11 0 R
  /Ascent 694
  /CapHeight 683
  /Descent -194
  /Flags 6
  /FontBBox [-40 -250 1009 750 ]
  /FontName /DJLCQW+CMR10
  /ItalicAngle 0
  /StemV 69
  /Type /FontDescriptor


% pfdtex
9 0 obj
  /FontFile 11 0 R
  /Ascent 694
  /CapHeight 683
  /CharSet (/A/C/D/E/I/L/M/N/P/Q/S/U/V/a/b/c/comma/d/e/f/g/h/hyphen/i/j/l/m/n/o/one/p/period/q/r/s/t/u/v/w/y)
  /Descent -194
  /Flags 4
  /FontBBox [ -40 -250 1009 750 ]
  /FontName /QJZLYL+CMR10
  /ItalicAngle 0
  /StemV 69
  /Type /FontDescriptor
  /XHeight 431

Both have different entries referring to the font file (/FontFile3 and /FontFile). According to the table 126 "Embedded font organization for various font types" in the PDF specification, the entry /FontFile refers to a Type1 font program and /FontFile3 to whatever the subtype in the referred stream is. So we need to take a look at object #11 in the dvipdfm file:

11 0 obj
  /Subtype /Type1C
  /Length 12 0 R

So it is Type1C, which is according to the same table in the PDF spec: "Type 1–equivalent font program represented in the Compact Font Format (CFF), as described in Adobe Technical Note #5176, The Compact Font Format Specification."

To find out what the secret of CFF is, a look at the introduction of "The Compact Font Format Specification" suffices:

Principal space savings are a result of using a compact binary representation for most of the information, sharing of common data between fonts, and defaulting frequently occurring data.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.