Thanks for that Hraban.

I guess after more than 30 years of typesetting academic books and journals in plain TeX (of whatever variety) it's hard not to think in plain TeX terms, but I will acquire more expertise in ConTexT as time goes by.

I appreciate, of course, that the nano-setting of the height parameter is never going to be the way forward, but this started when I noticed that a very slight alteration (of a few points) made the difference between 39 and 41 lines on the first full page of text, while no whole number resulted in 40 lines - hence the repeated addition of tiny amounts to see if the magic value would emerge that simply sets 40 lines of 12pt text on every page. Nothing so far has allowed this to happen.

I did immediately think about paragraph penalties (none of which I have set up myself), but there are no widows (unacceptable) or orphans (perfectly acceptable to those who read old books!) that could be generating this curious effect. The one page that is consistently a line short can't be improved by plain TeX's \looseness command, but I expect ConTexT has an equivalent that does work - I do use it regularly, in particular to reduce the gap between text and footnotes to as near to an optimal 6 points as I can manage.

Best wishes

John 🇪🇺 Слава Україні! 🇺🇦

On Mon, 23 Jun 2025 at 15:39, Henning Hraban Ramm <texml@fiee.net> wrote:

Am 23.06.25 um 14:56 schrieb John Was:
> Thanks Hraban. I actually started out with just one setting for the
> height, but have been adding more to see if I could achieve what ought
> to be a very simple result by changing some of the others Nothing has
> worked so far, even when I vary the choice of what to switch on and
> off. The most intriguing is:
>
> height=522.6275pt
>
>
> with which I have been tinkering endlessly. I don't really see why I
> need this at all since it should be automatically calculated from the
> other settings, but it does make a difference, though in an unexpected
> way. If I make just a minute alteration (plus or minus) I can achieve
> 39 lines or 41 lines, but never 40, on the first few pages. There is no
> logical reason I can think of in any case why three pages should be
> correct and three incorrect, but I'll keep at it until it comes right.
>
> I had already found \showgrid but I can't use grid setting throughout
> the books I am intending to set with ConTexT since a typical page will
> consist at least of main text with 12 points between the lines and
> footnotes with 9 points between the lines, and often also extended
> quotations with 11 points between the lines. But I will need to ensure
> that all pages come to the same depth.

The "lines" setting always works with the current bodyfontsize and isn’t
suited for changing font sizes (i.e. changing interlinespacing). That
you can’t seem to achieve exactly 40 lines is probably due to some
paragraph breaking penalties.

It makes no sense to set "height" or anything else in nanometer accuracy.

Just in case:
– height includes header and footer and their distances
- it’s not possible to define \textheight directly
– width is just the line width without margins
- you can also just define margings, header and footer and set height
and width to "fit".

Generally I got the impression that you’re trying to use ConTeXt with a
plain TeX mindset. That works only if you know ConTeXt in depth as well
as TeX. (If you try to tune a computer with a soldering iron, you need
to know it very well…) I can’t help you on that level, I’m just a
longtime user with a media designer’s mindset.

Hraban
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