# Kerning between V and / in Palatino and Euler

Edit 1

I made the test with real palatino font and Neo-Euler, with the same result (As far as I can see)

\documentclass{standalone}
\usepackage{fontspec}
\setmainfont[] {PalatinoLTStd-Roman.otf}
%\setmathrm [] {}
\usepackage{unicode-math}
\setmathfont[math-style=upright]{euler.otf}
\usepackage{siunitx}

\begin{document}

\begin{tabular}{ll}
Text  & MV/m \\
equation & $MV/m$\\
two mathrm & $\mathrm{MV}/\mathrm{m}$\\
one mathrm & $\mathrm{MV/m}$\\
siunitx & \si[per-mode = symbol]{\mega\volt\per\metre}
\end{tabular}

\end{document}


Original

I am using palatino with euler as shown below.

I noticed a big space between V and /. I am not sure if it is because the slash is a binary operator or because the kerning is incorrect. I have this problem with the unit and it shown also with siunitx. Do you also think it is too much space?

\documentclass{standalone}

\renewcommand{\rmdefault}{ppl} % rm
\usepackage[scaled]{helvet} % ss
\usepackage{courier} % tt
\usepackage{eulervm} % a better implementation of the euler package (not in gwTeX)
\normalfont
\usepackage[T1]{fontenc}
%\usepackage{verbatim}
\usepackage{siunitx}

\begin{document}

\begin{tabular}{ll}
Text  & MV/m \\
equation & $MV/m$\\
two mathrm & $\mathrm{MV}/\mathrm{m}$\\
one mathrm & $\mathrm{MV/m}$\\
siunitx & \si[per-mode = symbol]{\mega\volt\per\metre}
\end{tabular}

\end{document}


• Unfortunately, the Palatino font metric file has no kerning between V and /; the situation is the same with TeX Gyre Pagella. This might be a feature request for the TeX Gyre team (I don't think anything can be done for ppl now). – egreg Jun 10 '13 at 21:23

If you modify your MWE to use article (to avoid artefacts of standalone) and add \showoutput to your document you will see that

Text  & MV/m \\


produces

........\T1/ppl/m/n/10 M
........\T1/ppl/m/n/10 V
........\T1/ppl/m/n/10 /
........\T1/ppl/m/n/10 m


So there is no font-specified kern between V and / in that font.

equation & $MV/m$\\


produces

........\U/zeur/m/n/10 M
........\U/zeur/m/n/10 V
........\kern0.83
........\kern-0.56
........\U/zeur/m/n/10 =
........\U/zeur/m/n/10 m


Net result is a small positive kern here, but note the / is from a different font.

looking in uzeur.fd we see this font is zeurm10 and looking at the output of

tftopl zeurm10


we see

(CHARACTER C V
(CHARWD R 0.646)
(CHARHT R 0.691)
(CHARIC R 0.083)


So V has a italic correction of .83pt which accounts for the first kern added.

the same file also has

 (LABEL C V)
(KRN O 177 R 0.056)
(KRN O 75 R -0.056)


which says there is a kern of -.56pt between (C)haracter V and (Oc)ctal 75 which is hex 61 which is = the slot with / in this encoding.

two mathrm & $\mathrm{MV}/\mathrm{m}$\\


produces

........\hbox(6.97992+0.15997)x16.67993
.........\OT1/ppl/m/n/10 M
.........\OT1/ppl/m/n/10 V
........\U/zeur/m/n/10 =
........\OT1/ppl/m/n/10 m


No kern, / again coming from the math font.

and

one mathrm & $\mathrm{MV/m}$\\


produces

........\hbox(7.48999+2.5)x30.52988
.........\OT1/ppl/m/n/10 M
.........\OT1/ppl/m/n/10 V
.........\U/zeur/m/n/10 =
.........\OT1/ppl/m/n/10 m


No kern again.

siunitx & \si[per-mode = symbol]{\mega\volt\per\metre}


produces

........\hbox(7.23492+1.20496)x31.56982
.........\T1/ppl/m/n/10 M
.........\T1/ppl/m/n/10 V
.........\T1/ppl/m/n/10 /
.........\T1/ppl/m/n/10 m


the same setting as for text with / coming from the same font as the letters with no kerning.

• Strange how 0.083 translates to 0.83pt... – Werner Jun 10 '13 at 21:36
• @Werner the tfm lengths are multiples of the design size which is 10pt here. – David Carlisle Jun 10 '13 at 21:38
• i would expect no negative kerning in a math font; after all, the normal situation is for alphabetic elements in a math expression to be considered as multiplying one another, hence the usual positive italic correction (even sometimes in an upright font). – barbara beeton Jun 10 '13 at 21:50
• @barbarabeeton I think I got the explanation of the -.56pt kern correct (feel free to downvote me if not:-) Or perhaps the comment was on the font, not my answer, in which case don't shoot the messenger:-) – David Carlisle Jun 10 '13 at 22:00