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Metric 'font-size'

From: Christoph Päper <christoph.paeper@crissov.de>
Date: Tue, 22 Aug 2006 21:34:16 +0200
Message-Id: <C138ADAF-AFA4-4D1F-B862-31514C6E6032@crissov.de>
To: www-style@w3.org

In <http://www.cl.cam.ac.uk/~mgk25/metric-typo/> Markus Kuhn writes  
about metric font sizes. You can use 'font-size' with millimetres and  
centimetres already, which is good, but I wonder whether we could add  
|q| as an alias for quarter an millimetre like according to that  
document Japanese typographers traditionally use (the linked source  
is a 404 though) and DIN 16507-2 proposes as a modulus.
(I hope nobody takes this as an excuse to request |dd| for Didot  
points of about three eighths of an millimetre, 0.376mm.)

<hr/>

I further thought a bit about font size keywords (currently | 
smaller|, |larger| and |xx-small| through |xx-large|) and whether one  
could incorporate traditional, irregular type size names (think X11^W  
SVG colour names). Just for fun, actually. This table, based upon the  
one from the aforementioned article, is what I came up with, using  
Wikipedia and <http://www.sizes.com/tools/type.htm> and inserting  
some Continental names (in brackets), where English ones weren't  
enough. (It wouldn't have been any effort to just list the English  
point--name relations, this one is metrified.)

  Font Size	|	 Font Height	 Font Size Name
(mm)	(Q)	|	(mm)	(pt)
----	---	+	----	----	-------------------------------
  1	  4	|	 0.7	 2.0	 Excelsior, Minikin
  1¼	  5	|	 0.9	 2.6	 Brilliant
  1½	  6	|	 1.1	 3.1	 Diamond
  1¾	  7	|	 1.3	 3.6	 Pearl
  2	  8	|	 1.4	 4.1	 Agate, Ruby
  2¼	  9	|	 1.6	 4.6	 Nonpareil; Emerald, Minionette
  2½	 10	|	 1.8	 5.1	 Minion/Mignon; (Insertia)
  2¾	 11	|	 2.0	 5.6	 Brevier
  3	 12	|	 2.2	 6.1	(Colonel)
  3¼	 13	|	 2.3	 6.6	 Bourgeois
  3½	 14	|	 2.5	 7.1	 Long Primer
  3¾	 15	|	 2.7	 7.7	(Corpus, Garmond)
  4	 16	|	 2.9	 8.2	 Small Pica
  4¼	 17	|	 3.1	 8.7	 Pica
  4½	 18	|	 3.2	 9.2	(Cicero)
  5	 20	|	 3.6	10.2	 English; (Medium)
  5½	 22	|	 4.0	11.2	 Columbian
  6	 24	|	 4.3	12.2	 Great Primer; (Tertia)
  7	 28	|	 5.0	14.3	 Paragon
  8	 32	|	 5.8	16.3	 Double Small Pica
  9	 36	|	 6.5	18.4	(Double Cicero)
10	 40	|	 7.2	20.4	 Double English
12	 48	|	 8.6	24.5	 Double Great Primer
14	 56	|	10.1	28.6	 Double Paragon
16	 64	|	11.5	32.7	 Meridian / Trafalgar
18	 72	|	13.0	36.7	 Canon; (Concordance)
20	 80	|	14.4	40.8	(Missal)
22½	 90	|	16.2	45.9	(Sabon)
25	100	|	18.0	51.0	
27½	110	|	19.8	56.1	
30	120	|	21.6	61.2	
35	140	|	25.2	71.4	

Using the CSS 2.1 draft one can relate these somewhat to current names.

15.7 Font size: the 'font-size' property
/*  font[size="7"]	{font-size: ;}*/
h1, font[size="6"]	{font-size: xx-large;}
h2, font[size="5"]	{font-size: x-large;}
h3, font[size="4"]	{font-size: large;}
h4, font[size="3"]	{font-size: medium;}
h5, font[size="2"]	{font-size: small;}
/*			{font-size: x-small;}*/
h6, font[size="1"]	{font-size: xx-small;}

(There really should have been a 1:1 relationship.)

Appendix D. Default style sheet for HTML 4
h1	{font-size: 2.00em;}	
h2	{font-size: 1.50em;}	
h3	{font-size: 1.17em;}	
h4	{font-size: 1.00em;}
h5	{font-size: 0.83em;}	
h6	{font-size: 0.75em;}	

(Should 'font' be handled in the HTML4 CSS, by the way?)

A common default font size (|medium|, |1em|) is 16px or 12pt (= 1pc),  
which is exactly the same at 96dpi. That data combined gives us:

          	px	pt	pc	mm	
--------	-----	--	----	-----	------------
xx-large	32	24	2	8.467	Double Pica
x-large 	24	18	1.5	6.350	Great Primer
large   	18.67	14	1.17	4.953	English
medium  	16	12	1	4.233	Pica
small   	13.33	10	0.83	3.514	Long Primer
x-small 	-	-	-	-      	-
xx-small	12	 9	0.75	3.175	Bourgeois

Rounded to metric values and using my name table above instead of the  
one from the 19th century:

          	 mm	Q	 em	
--------	----	--	----	---------------------------
xx-large	8.50	34	2	(Double Pica)
x-large 	6.25	25	1.47	(Great Primer, Tertia: 24q)
large   	5.00	20	1.18	 English
medium  	4.25	17	1	 Pica
small   	3.50	14	0.82	 Long Primer
x-small 	-	-	-	 -
xx-small 	3.25	13	0.76	 Bourgeois

There sadly is neither a round pt nor Q size for |x-small|.

In the standard Mac OS X font selection you find these pt sizes  
predefined, other software uses similar values:

pt	 in  	   mm	 ~mm	 ~Q
---	-----	-------	-----	------	--------------------
   9	 1/8 	  3,175	 3-3¼	 12-13	 Bourgeois
  10	 5/36	  3,528	 3½	 14	 Long Primer
  11	11/72	  3,881	 3¾-4	 15-16	 Small Pica
  12	 1/6 	  4,233	 4¼	 17	 Pica
  13	13/72	  4,586	 4½	 18	(Cicero)	
  14	 7/36	  4,939	 5 	 20	 English
  18	 1/4 	  6,35	 6¼	 25-26	 Great Primer
  24	 1/3 	  8,467	 8½	 34	 Double Pica
  36	 1/2 	 12,7	12½	 50	 Double Great Primer
  48	 2/3 	 16,933	17 	 68	 Canon
  64	 8/9 	 22,578	22½	 90	
  72	1    	 25,4	25 	100	(Inch)
  96	 4/3 	 33,867	33¾	135	(Double Canon)
144	2    	 50,8	50 	200
288	4    	101,6	100	400		
Received on Tuesday, 22 August 2006 19:34:22 GMT

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