UK TeX FAQ -- question label widows

### Controlling widows and orphans

Widows (the last line of a paragraph at the start of a page) and orphans (the first line of paragraph at the end of a page) interrupt the reader’s flow, and are generally considered “bad form”; (La)TeX takes some precautions to avoid them, but completely automatic prevention is often impossible. If you are typesetting your own text, consider whether you can bring yourself to change the wording slightly so that the page break will fall differently.

The (La)TeX page maker, when forming a page, takes account of variables `\``widowpenalty` and `\``clubpenalty` (which relates to orphans!). These penalties are usually set to the moderate value of `150`; this offers mild discouragement of bad breaks. You can increase the values by saying (for example) `\``widowpenalty``=500`; however, vertical lists (such as pages are made of) typically have rather little stretchability or shrinkability, so if the page maker has to balance the effect of stretching the unstretchable and being penalised, the penalty will seldom win. Therefore, for typical layouts, there are only two sensible settings for the penalties: finite (150 or 500, it doesn’t matter which) to allow widows and orphans, and infinite (10000 or greater) to forbid them.

The problem can be avoided by allowing the pagemaker to run pages short, by using the `\``raggedbottom` directive; however, many publishers insist on the default `\``flushbottom`; it is seldom acceptable to introduce stretchability into the vertical list, except at points (such as section headings) where the document design explicitly permits it.

Once you’ve exhausted the automatic measures, and have a final draft you want to “polish”, you should proceed to manual measures. To get rid of an orphan is simple: precede the paragraph with `\``clearpage` and the paragraph can’t start in the wrong place.

Getting rid of a widow can be more tricky. Options are

- If the previous page contains a long paragraph with a short last line, it may be possible to set it ‘tight’: write `\``looseness``=-1` immediately after the last word of the paragraph.
- If that doesn’t work, adjusting the page size, using `\``enlargethispage{`\``baselineskip`}` to ‘add a line’ to the page, which may have the effect of getting the whole paragraph on one page.
- Reducing the size of the page by `\``enlargethispage{-`\``baselineskip`}` may produce a (more-or-less) acceptable “two-line widow”.

Note that `\``looseness``=1` (which should increase the line length by one) seldom has the right effect — the looser paragraph typically has a one-word final line, which doesn’t look much better than the original widow.

This question on the Web: http://www.tex.ac.uk/cgi-bin/texfaq2html?label=widows