# Poor Kerning in pdfLaTeX output, am I doing something wrong?

Just for the sake of clarity I'm using Linux Mint 17, with TeX Live. I'm using TeXworks to edit my TeX code. Here is the LaTeX code I'm using:

\documentclass{article}
\begin{document}
Very Keen Katz
\end{document}


The problem I've noticed is that kerning seems to be very poor in my output. I say "seems" because, since I'm kind of a TeX neophyte, I'm not sure if my issues is merely typographical ignorance. I don't think that's the case here, but one can never be certain.

With all that out of way, here's a screenshot I made to show the issue I'm having:

(I apologize for the small red lines, but since we're talking about rather small margins, I didn't want the lines to hide the issue.)

Anyway, the first row is a screenshot of the output from pdfLaTeX. In the second row, I basically manually kerned the output in the first row using GIMP. The third row is a semi-separate issue (that might be related) that I'll get to in a moment. So if you look at the first row, you can see that in "Very" the "e" is at least partially kerned, there a slight overlap between the edge of the "V" and it. However, in "Keen" there does not appear to be any kerning whatsoever. I am not sure if that is just how it's supposed to be, or if I'm doing something wrong, but it certainly doesn't look right to my eyes.

Now, getting to the third issue, if you'll take a look at the "V" you'll see that the bottom descends a little below the "underline" (I'm not sure what the right term is) of "ery". In the third row, I tried to manually fix this. Now, is that just how "V" is supposed to look in Computer Modern, or is there something wrong here?

• It is all about greyness, and in my pov the two last lines have the Ve like big black lumps. They are really too close. Jan 6 '15 at 8:55
• Try out package microtype. It does some magic to the text. Jan 6 '15 at 8:55
• I'm not quite sure what you are after here in terms of something being 'wrong'. The output you get seems 'to be expected' to me in the sense that this is the design of Computer Modern. The 'artistic' side of kerning is a design decision so in itself it's really not on topic. Perhaps you want to adjust the kerning 'in the document'? Jan 6 '15 at 9:17
• @Johannes_B: microtype won't change the kerning. Jan 6 '15 at 9:38
• There is no "right" or "wrong" about kerning choices it is simply a design choice, and while one could argue about some of the kerns (or lack of kerns) in computer modern, given a choice of the three forms above I'd pick the first, the second two just look squashed Jan 6 '15 at 9:39

The choice of inter-letter kerns is not done by TeX but by the font designer, Although in your case you are using Computer Modern so the font designer and the designer of TeX are the same person.

You can see which kerns have been added by adding \showoutput to your document.

...\hbox(6.83331+1.94444)x345.0, glue set 259.69434fil
....\hbox(0.0+0.0)x15.0
....\OT1/cmr/m/n/10 V
....\kern-0.83334
....\OT1/cmr/m/n/10 e
....\OT1/cmr/m/n/10 r
....\OT1/cmr/m/n/10 y
....\glue 3.33333 plus 1.66666 minus 1.11111
....\OT1/cmr/m/n/10 K
....\OT1/cmr/m/n/10 e
....\OT1/cmr/m/n/10 e
....\OT1/cmr/m/n/10 n
....\glue 3.33333 plus 1.66666 minus 1.11111
....\OT1/cmr/m/n/10 K
....\OT1/cmr/m/n/10 a
....\OT1/cmr/m/n/10 t
....\OT1/cmr/m/n/10 z


Showing that the only kern added is between V and e. Of course that isn't the full story about white space between the letters as the font designer can also specify the advance width of each character which may be wider or in some cases less wide than the visible width of the actual glyph, so affecting the sidebearings of the characters.

If you choose a different font you get different results, here, much smaller inter-word spaces, and additional kerns between K and e and r and y.

\documentclass{article}
\showoutput
\usepackage{tgpagella}
\begin{document}
Very Keen Katz
\end{document}


...\hbox(6.99998+2.81999)x345.0, glue set 261.2501fil
....\hbox(0.0+0.0)x15.0
....\OT1/qpl/m/n/10 V
....\kern-0.9
....\OT1/qpl/m/n/10 e
....\OT1/qpl/m/n/10 r
....\kern0.15
....\OT1/qpl/m/n/10 y
....\glue 2.5 plus 1.25 minus 0.83
....\OT1/qpl/m/n/10 K
....\kern-0.2
....\OT1/qpl/m/n/10 e
....\OT1/qpl/m/n/10 e
....\OT1/qpl/m/n/10 n
....\glue 2.5 plus 1.25 minus 0.83
....\OT1/qpl/m/n/10 K
....\OT1/qpl/m/n/10 a
....\OT1/qpl/m/n/10 t
....\OT1/qpl/m/n/10 z

• I see! Thank you for the explanation! I didn't realize that kerning was a per-font thing. So I guess, if I understood correctly, in Computer Modern, there is no kern added with uppercase "k" ? Jan 6 '15 at 9:33
• @krfkeith I didn't check the entire kern table, just your example text, the font can specify kerns between each pair of letters. Certainly cmr doesn't have a kern between K and e Jan 6 '15 at 9:43
• The kern table, is it a file that can be manually edited? Jan 6 '15 at 9:58
• You can edit it but that means generating a new tfm file and then (for licence reasons if nothing else) renaming the font to something else and changing all the latex support files to load the font under a different name, and it's not just one font, even if you just want to edit cm roman, there is cmr{5,7,10,12,17} separate design size fonts all kerned separately. see tex.stackexchange.com/questions/110486/… Jan 6 '15 at 10:02

In most typefaces, letterforms with angled bottoms such as 'V' extend somewhat below the baseline, because the narrow point appears shorter to the eye than it really is.

Your manual kerning is very overdone. Remember that kerning is done to make the text 'look right', whatever that may mean, rather than to conform to some mathematically precise spacing between the letterforms.

• I can see the "Ve" kerning being overdone, but with "Ke" there doesn't appear to be any kerning whatsoever. Jan 6 '15 at 9:09
• @krfkeith Indeed, the 'V' and 'e' are too widely spaced, but I suppose that that is simply Prof. Knuth's choice in designing the typeface. Jan 6 '15 at 9:18
• did you mean the "K" and "e" ? Jan 6 '15 at 9:35
• Yes, yes I did. Jan 7 '15 at 2:17