PDF Explained

Errata for PDF Explained

Submit your own errata for this product.

The errata list is a list of errors and their corrections that were found after the product was released. If the error was corrected in a later version or reprint the date of the correction will be displayed in the column titled "Date Corrected".

The following errata were submitted by our customers and approved as valid errors by the author or editor.

Color key: Serious technical mistake Minor technical mistake Language or formatting error Typo Question Note Update

Version Location Description Submitted By Date submitted Date corrected
Page 14
"Document content", unordered list

The third item of the list describing syntax elements of PDF document states:

"Strings, introduced with brackets, like (The Quick Brown Fox)."

The word 'brackets' here is somewhat misleading, since '(' and ')' characters are commonly referred to as parentheses, and this term is used in PDF Specification as well. Moreover, PDF strings can be actually introduced with brackets (i.e., '<' and '>' characters), but it is a distinct syntax not mentioned in the book.

So, even if it is not technically a mistake, I'd suggest to replace 'brackets' with 'parentheses' here and in similar occurrences in the text.

Note from the Author or Editor:
Changed language at this location and throughout text. Confusion about international use of bracket/brace/parenthesis on my part.

valentinesinitsyn  Jan 05, 2012 
Page 14%
Location 368 of 2599

Since it's Mobi format, it has no page number, but it's at Location 368 of 2599 or 14%. It's in page number 8 of Chapter 1 in corresponding PDF version (real page number is 24 of 142), although this is already correct in PDF version.

In a bracket, it is currently
> (eXtensible Markup Langauge)

It should be
> (eXtensible Markup Language)

The typo is at "Language".

Note from the Author or Editor:
Thanks. The source is indeed correct, but there was some problem with the generation of the .mobi - it's being regenerated now.

Korrawit Pruegsanusak  Dec 08, 2012  Dec 11, 2012
Page 16
1st paragraph below "Building the Elements"

The line ending for Unix and Mac OS X is <LF>, not <CR>.

Note from the Author or Editor:
Erratum is confirmed. Fixed by the author in text.

Jochen Hayek  Jan 09, 2012 
Page 37
Sentence before the definition of the pdfobject data structure

"psuedocode" should read "pseudocode"

Note from the Author or Editor:
Fixed in production SVN.

feast:current john$ grep "psuedocode" *.xml
ch03.xml: <para>The following recursive data structure, given in psuedocode, can
feast:current john$ mvim ch03.xml
feast:current john$ svn commit
Sending ch03.xml
Transmitting file data .

Committed revision 580464.

BlaF  Apr 16, 2012 
Page 57
last sentence


What I noticed is a minor problem, but I send a note because it could be of interest anyway.

The last sentence reads:

"The number k is about 0.553."

It is. That is true! In such circumstances, 0.552 is commonly used as an approximation, though.

Details about Bézier optimization for circles are available on page 12-13 at:



Note from the Author or Editor:
Thanks. This was a rounding error on my part; I had misread 0.55228... as 0.5528... when reading a source.

Saašha Metsärantala  Jan 30, 2012 
Printed, PDF, ePub
Page 74
Table 6-1

In the third row, the parameter for Horizontal Spacing is listed as "Th", but under Operators, it says "Tz sets the horizontal scaling".
That's confusing.

It's also confusing to have the letters following the "T" in the table listed as subscripts under the Parameter heading, but described without subscript under "Operators" column.

Also "T", subscript "mode" is defined as "rendering mode", and described later as "Tr sets the text rendering mode to "render, an integer". Which leads one to wonder if there are other possible modes to use here than "r".

It's hard to tell what is code and what is variable values in this table.

It would be more clear if there were a sample use column.
"Tw 2" for Word spacing.

Note from the Author or Editor:
Hi Margery,

Thank-you for writing.

I have checked, and the table is correct. It is an amalgam of two tables from the ISO standard.

You are right, though, that it's a little confusing. Not least because the parameter names are not referenced in the following text at all.

If O'Reilly choose to fix it, I think an appropriate fix is to:

a) Delete the first column of the table; and then
b) Rename the (now first) column heading from "Description" to "Parameter"

I have marked this erratum as "Confirmed" in the system, but I leave it up to O'Reilly to decide whether action is warranted.


Margery  Nov 12, 2015 
Page 165
First example

In chapter 9, the first example under "Merging Documents" uses file1.pdf twice. The description in the following paragraph suggests the example should really be:

pdftk file1.pdf file2.pdf file3.pdf output output.pdf

Note from the Author or Editor:
The submitter is correct. The existing...

pdftk file1.pdf file1.pdf file3.pdf output output.pdf

..should read:

pdftk file1.pdf file2.pdf file3.pdf output output.pdf

Chris Ridd  Oct 01, 2021