# Strategies for corrections in book typeset with TeX

I have typeset a long book using TeX and now it is time to re-print it. This is an opportunity to incorporate corrections to the errata discovered in the initial printing.

Unfortunately TeX may completely change pagination, even with minimal changes to the text; but my publisher would like to re-print the minimum number of pages possible (and, of course, this would minimize the possibility of introducing new errors, badly printed pages, etc).

So I would like to know if there are any strategies I could follow in order to minimize changes to the pagination of my book.

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How many errors do you intend to fix, and on how many pages are they distributed? –  krlmlr May 10 '12 at 16:33
The book is ~800 pages long. My list of errata contains about 25 items on 20 pages. Most of them seem harmless, some will require more attention. –  nplatis May 10 '12 at 20:44
I am just wondering if the publisher really just prints the PDF you give them, or if they take the TeX source and do the fine-tuning by themselves. In the second case, of course, an editor will take care of that, and any manual fine-tuning on your behalf would be useless. –  krlmlr May 10 '12 at 21:57
They are a rather small publisher and they don't use TeX. So in order to fine-tune the book for the first printing we sat down with them and I implemented their suggestions to improve pagination. In the end they just used the PDF I produced. –  nplatis May 11 '12 at 6:05

Really you need to take control as TeX will try to do what it thinks right and the cost of reprinting pages isn't part of its formula.

On a page where you want to make a correction, if the correction is such that it could fit on the same page then:

• If you are deleting stuff so the page runs short add \newpage at the old page break to force the page to break at the same place.

• If you are adding stuff then if necessary use \enlargethispage{2\baselineskip} or whatever is the minimum amount you can get away with. Actually enlarging the page works best if you enlarge both pages on a two page spread by the same amount so you might consider using \enlargethispage{\baselineskip} on both pages on the spread which would allow you to flow a line from one page to the next. That does of course cause an extra page to be reprinted, but may produce a better final result.

If you can not contain the change to a single page, you can of course use similar techniques in a run of consecutive pages, using forced page breaks at the start and end to align with the page breaks on the previous addition but allowing text to reflow within that range to find better page breaks.

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For shortened pages, if the old page break happened in the middle of a paragraph then a nice trick is to place

 {\parfillskip0pt\par}\newpage\noindent


at the exact spot of the old page break.

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If you use \pagepreak even mid paragraph it will \vadjust itself on to the main vertical list so break the page without affecting the paragraph formatting. –  David Carlisle May 10 '12 at 18:22
If the paragraph that is broken across the is not modified, then @David's suggestion to simply use \pagebreakis the better one. If, however, that paragraph was modified the above solution might save reprinting the second page. However, artifically splitting a paragraph this way, means that TeX is potentially using different linebreaks in both parts (because of \adjdemeritsfor a start). That might lead to subtle changes further down, so it is absolutely essential to verify that the following page is still broken in the same way as in the privious printing! –  Frank Mittelbach May 11 '12 at 7:32

Before fiddling with the fine-tuning as David suggested, find out how many pages actually change if you just let TeX do its job. For this, I suggest the following:

• Take the original PDF (if possible the one that has been used for printing) and the one that has been produced after the corrections

• Convert each page of both PDFs to a raster image and compare them pixel by pixel. A low-resolution image will do for the first pass.

This answer on StackOverflow shows how to do the PDF -> TIFF -> compare task.

My feeling is that you will get surprisingly few different pages other than those where content has changed. Though, the worst case is that all pages change because of differences in the TeX environment (TeX binaries, packages, ...).

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Interesting. I will try that and see how it goes. The original printing is two years old; I hope the TeX environment itself won't cause such changes, but just in case I do have a backup of my full TeX installation of that time. –  nplatis May 11 '12 at 6:06