# How can I adjust the fontsize of greek letters only?

I am using \amsbook with package \mathptmx. The fontsize of all Greek letters in math mode is about 12% larger than for non-Greek. What is it that controls the default size of each font, please?

• Do \usepackage{newtxtext,newtxmath} instead of \usepackage{mathptmx} (the latter package is essentially a kludge for getting Times also in math with the limited resources available 20 years ago). – egreg Jan 5 '17 at 12:03

You can't, I'm afraid. Not without substantial work, at least.

The package mathptmx does

\DeclareSymbolFont{letters}{OML}{ztmcm}{m}{it}


and if we look at omlztmcm.fd we find

\DeclareFontShape{OML}{ztmcm}{m}{it}{<-> zptmcm7m}{}


Now we can look at the output of vftovp zptmcm7m, we see

(VTITLE )
(FAMILY UNSPECIFIED)
(FACE F MRR)
(CODINGSCHEME TEX MATH ITALIC)
(DESIGNSIZE R 10.0)
(COMMENT DESIGNSIZE IS IN POINTS)
(COMMENT OTHER SIZES ARE MULTIPLES OF DESIGNSIZE)
(CHECKSUM O 21074766077)
(SEVENBITSAFEFLAG TRUE)
(FONTDIMEN
(SLANT R 0.277)
(SPACE R 0.0)
(STRETCH R 0.0)
(SHRINK R 0.0)
(XHEIGHT R 0.440991)
(EXTRASPACE R 0.0)
)
(MAPFONT D 0
(FONTNAME psyro)
(FONTCHECKSUM O 37333711466)
(FONTAT R 1.0)
(FONTDSIZE R 10.0)
)
(MAPFONT D 1
(FONTNAME cmmi10)
(FONTCHECKSUM O 1350061076)
(FONTAT R 1.0)
(FONTDSIZE R 10.0)
)
(MAPFONT D 2
(FONTNAME ptmri8r)
(FONTCHECKSUM O 32105367571)
(FONTAT R 1.0)
(FONTDSIZE R 10.0)
)


at the start and later

(CHARACTER O 13
(CHARWD R 0.630994)
(CHARHT R 0.4935)
(CHARDP R 0.016992)
(CHARIC R 0.082996)
(MAP
(SETCHAR C a)
)
)


which means that \alpha points to the a glyph in psyro (an oblique version of the standard PostScript font Symbol).

You have to rebuild the virtual font files for zptmcm7m by doing something like

(MAPFONT D 0
(FONTNAME psyro)
(FONTCHECKSUM O 37333711466)
(FONTAT R 0.89)
(FONTDSIZE R 10.0)
)


but also all metrics should be changed accordingly by hand, so the code for \alpha should become

(CHARACTER O 13
(CHARWD R 0.56158)
(CHARHT R 0.439215)
(CHARDP R 0.015123)
(CHARIC R 0.073867)
(MAP
(SETCHAR C a)
)
)


and so on for all other Greek letters.

The mathptmx package, with the accompanying fonts is essentially a kludge for being able to emulate Times fonts with the limited resources available twenty years ago. Nowadays you can get better results with

\usepackage{newtxtext}
\usepackage{newtxmath}

• egreg Are we saying that Worldwide, and for years, people are putting-up with miss-matching Greek fonts throughout their mathematics? I've been using, e.g. \newcommand{\lambdasmall}{\scalebox{0.93}[0.93]{$\lambda$}} % and I thought I was plain daft. – keith77777 Jan 5 '17 at 15:45
• @keith77777 Unfortunately, some document classes (IEEE, for instance) continue to suggest mathptmx; some still do \RequirePackage{times}, go figure! :-( – egreg Jan 5 '17 at 15:48
• egreg Your solution does appear to work except that it gives an error: package clash with package \textcomp (not even present). – keith77777 Jan 5 '17 at 20:13
• @keith77777 It must be some other package you load – egreg Jan 5 '17 at 21:48
• egreg It appears to be that newtxtext needs to be loaded before libertine. Anyway, that has fixed the error in my case. Many thanks for your help. – keith77777 Jan 6 '17 at 13:57