I think it's useful if I first clarify the context of this question to help understand it. I'm compiling a mathematical LaTeX book that will be printed by the in-house printing service at my university. This is the second edition. The preamble starts as follows:
\documentclass[a4paper, 12pt]{book}
\usepackage[top=2.54cm,bottom=2.54cm,left=2.54cm,right=2.54cm,footskip=23pt]{geometry}
\usepackage{parskip}
...
When the first edition was printed, I noticed that the text was slightly bigger than it seemed in PDF, and more importantly, I noticed that the margins had shrunk in various directions, which was impractical for students who wanted to take notes there. After doing some geometry, my conclusion is that the printing service does some unspecified upscaling of the page content.
Now, I want to measure precisely how much scaling and shifting is being done. I have a rough idea based on the first edition, but they have allowed me to print a single test copy, and I want to put this to full use. So, I want to print a special page that has various calibration widgets on it.
What's the best way to engineer such a "calibration page"? It could either be:
- A full-page overlay that shows all the dimension lines of the content rendered by TeX. I've seen
\usepackage[showframe]{geometry}suggested for this, but it seems too bare-bones. The figure produced by thelayoutpackage is not to scale, so that won't work. Perhaps it would ideally look like the image in this question, but then with all the numbers well-inside the page so that they don't fall off. - A minimal figure somewhere on the page that clearly shows the entire linear transformation. A single 5-centimeter line can show scaling, for example, but then I'm not sure how to find the offset.
I want to note four points:
- The transformation is different for the left- and right-hand page of a spread;
- It's physically impossible to measure any length that falls into the fold of the book;
- The transformation is linear, keeps orientation, and scales the same horizontally as it does vertically.
- Some guides, e.g. a simple border around the page, won't work, because they'll fall off the printer and hence can no longer be located.
croppackage. – Jasper Habicht Aug 08 '22 at 21:43