How to change margins in page setup from metric to inches
I am using Firefox 47.0 on Windows 10 and find that if I print a page from the browser, page setup shows metric units. (if I print from any other application, that application's interface for setting margins use inches. I admit I haven't test every single other application.) In earlier versions I found forum discussion suggesting that the units were selected according to the paper size. That may once have been true, but I never experienced that in years past. In fact, when I select paper size in the printer driver, the interface shows both the metric and inch dimensions of the sheet or letter.)
I could learn to work with metric when I am printing from Firefox, but would prefer not to have to do so, as I have a lot of settings memorized since I print the same type of material frequently. But I can as easily get out a metric ruler as one with inches when I measure where want to place the (reduced) page image. So, if you have an easy answer, great; if not, I can live with it.
In trying to solve this, I followed a forum suggestion and refreshed Firefox. That did not solve the problem, but, as expected, introduced a number of others that I have fixed. There may be more. The units of measure problem predates the refresh, but is still recent, possibly arising with the update to version 47.
As an aside, I had discovered and documented for myself, how to "fake" Firefox (many versions ago) into remembering the page size I wanted to use. It is cumbersome enough that I now use that trick only when switching between letter and legal. I print on any piece of paper big enough to feed through the printer and with enough white space to hold what I want to print. I let the printer driver think it is working with either of those two, and set margins accordingly to force the image onto the smaller sheet. When one does a lot of this, it becomes almost second nature.
However, I would be nice if one could set the page size preference in Printing Preferences in Control Panel | Devices and Printers, and have Firefox pick that up (as it does other preferences, and as all the other applications I use do).
Alle antwurden (3)
The unit measures are influenced by the paper size that is selected thru Firefox. Firefox is a cross-operating system application - Windows, Mac, Linux and others - most user 'print' setting are set and saved within Firefox. IOW, system defaults aren't necessarily used in Firefox. Although MacOSX does seem to have more "native" support than the other OS's. Using Printing Preferences in Control Panel | Devices and Printers doesn't 'translate' well to Mac & Linux, from the little bi I have used those OS's.
US paper sizes such as Letter & Legal (along with US enveloper and postcard sizes, & most photo paper sizes) will use inch measurements, while the international paper sizes - the "A" papers - will be metric
https://support.mozilla.org/en-US/kb/how-print-web-pages-firefox See the Print window settings dialog box in that KB article. Hit the Properties button in the upper-right corner to access the Paper Size selector for Firefox. Once you get the correct paper size set the 'measurements' should match the paper size that is set.
I say should because there are few Bugs related to changes made for Electrolysis / e10s the screw up those mm/inch measurements ad may give the user a mixture. Seems to affect the Right Margin setting more than the Left or Top & Bottom Margins.
Finally, here's a KB article - https://support.mozilla.org/en-US/kb/pages-appear-tiny-when-i-print-or-print-preview-firefox - particular to a problem seen in Firefox 47.
Within Firefox, I have for years been using Page Setup and have almost always had letter size selected in the printer dialog window. The only other size I ever use (in Firefox) is Legal. Letter is selected right now, and the Margins and Header/footer tab on Page Setup displays all margins in metric.
I again, just now, using Google, found a Mozilla forum entry addressing this problem several several years ago. I remember making a change to prefs.js via the about:config URL. I looked at that again and found that print.<my printer>_print_paper_size_unit value was 1. According to that old advice, that meant default paper size was A4. I didn't note what value I set it to a few days ago, but just set it to 0 for Letter size as default. I closed the URL and opened prefs.js in Wordpad to see that the change was stored. Page Setup still shows metric margins. I presume closing Firefox and restarting it will not make any difference. If it does, and the problem is fixed, I will come back to this and note that fact.
This is a new problem, perhaps in version 47 or perhaps a recent version before 47. I can't be sure what updates may have occurred while this has been a problem, but I have changed the update option from automatic to "ask me" so I can be more sure of when any new problem arises.
Small update: Upon restarting Firefox, the problem is not solved, while I can see that my change to prefs.js remains intact. This is pretty much what I expected.