fonts
My document has ptm as \rmdefault and math is typeset using MTpro2. I would like to change the font of the upright characters for mathematics to match the font used in the body of the document. For example, anything written as \mathrm{cos} or \cos should use the same font as the body of the document.
That way I could stop using \text{cos} whenever I want upright letters in the math which matches the font used for the body, which is annoying.
How can I do that?
Computer Modern's greek (bottom) font is (loosely) based on Monotype's 155M Greek font (top):
The Monotype 155M font itself is related to the Porson greek font, which was one of the most used typeface for greek in english speaking countries. One of the characteristic of this font is that it has upright capitals but slanted lowercase. This might seem surprising today, but the first italic fonts all had upright capitals (see for example the image of the Aldine Press article on wikipedia)
Notice that in France, the traditional font for greek was Didot's, which has both upright capitals and lowercase, which is why using upright lowercase greek was standard in France.
You can see versions of the Didot and Porson fonts on the Greek Font Society website.
I realize I’m a few years late here, but as of 2018, we can stop doing workarounds like the earlier answers, clever and impressive as they are.
The simplest approach is just to load unicode-math and use \symup{\alpha} and so on, or to get that by default, load unicode-math with the [math-style=upright] option. Latin Modern Math, the default math font for unicode-math, contains an upright Greek math alphabet, and so so most other OpenType math fonts.
The Computer Modern Unicode project has a font very similar to the unslanted italics: CMU Serif Upright Italic. (It does not come in bold, but you might fall back on the FakeBold= feature from fontspec or use the defaults.) You can load this only for upright math letters, as follows:
\documentclass[varwidth, preview]{standalone}
\usepackage[math-style=upright]{unicode-math}
\setmathfont{Latin Modern Math}
\setmathfont[range=up/{Latin,latin,Greek,greek}]{CMU Serif Upright Italic}
\begin{document}
\( \alpha + \beta = \pi \)
\end{document}
You can also load this font with the fontspec package, and there’s an option to load it to replace the italic font in the CMU family, or load it as the normal font and the slanted italic as its companion.
Best Answer
Doing
\renewcommand{\rmdefault}{ptm}is not sufficient for the purposes of math.Load
mathptmxbeforemtpro2or, even better,newtxtext:The following is my recommended version with
newtxtext: