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Re: bolder/lighter defintion

From: John Daggett <jdaggett@mozilla.com>
Date: Mon, 18 May 2009 22:03:18 -0700 (PDT)
To: Thomas Phinney <tphinney@cal.berkeley.edu>
Cc: www-style <www-style@w3.org>
Message-ID: <25040285.87571242709398496.JavaMail.root@cm-mail01.mozilla.org>

Thomas Phinney wrote:

> There are probably other issues with this chart lookup, but the one that
> leaps to mind is assuming that all fonts will have values that fall in
> nice even 100s. Other values are not terribly unusual (for various
> reasons mostly related to application architecture limitations on
> Windows).

I realize that the implementation details of this can get messy and the
rules for mapping weights onto this 9-point scale are not always clear.
For fonts available on a given system, most user agents rely on platform
API's to determine these mappings.  GDI has its mappings, ATS a slightly
different set of mappings and fontconfig another set.  The spec wording
already alludes to the problems of mapping a given scale onto this 100 -
900 scale:

> Font formats that use a scale other than a nine step scale should map
> their scale onto the CSS scale so that 400 roughly corresponds with a
> face that would be labeled as Regular, Book, Roman and 700 roughly
> matches a face that would be labeled as Bold. Or weights may be inferred
> from the style names, ones that correspond roughly with the scale above.
> The scale is relative, so a face with a larger weight value should never
> appear lighter. If style names are used to infer weights, care should be
> taken to handle variations in style names across locales. 

Is there a better wording for this?  One that would reflect common
practice in greater detail?  Just as an example, ATS on Mac OS X uses
the style name to do this mapping or the OS/2 weight if it doesn't
recognize the style name.  Do you think the spec needs this level of
detail, along with a way of specifying how to map weights like 275 or
650?

Given your knowledge of Adobe fonts, I'm wondering if you have any
insight into why weights that are not multiples of 100 are used in
general.  Are the reason primarily historical, related to Multiple
Master fonts or some sort of hinting consideration?  Or GDI-related
problems?

I analyzed the fonts in Adobe Font Folio 11.  Of the 2406
faces, roughly 7% had weights that were not multiples of 100.  The
breakdown is:

  250:      18
  275:      10
  350:       2
  450:       8
  550:       7
  650:       2
  750:      72
  850:      30
  950:      12
  
Is there a reason for never defining font weights lower than 250? 
Listed below are the weights for the HelveticaNeueLTStd family.  Why do
the Thin and UltraLight faces use 250 and 275, instead of 100 and 200 as
suggested in the OpenType spec for faces called "Thin" and "UltraLight"?

OS/2 weight class definitions:
http://www.microsoft.com/typography/otspec/os2.htm#wtc

Weights for faces in HelveticaNeueLTStd family (based on OS/2 weight class):

250 HelveticaNeueLTStd Thin 
250 HelveticaNeueLTStd Thin Condensed 
250 HelveticaNeueLTStd Thin Condensed Oblique 
250 HelveticaNeueLTStd Thin Extended 
250 HelveticaNeueLTStd Thin Extended Oblique 
250 HelveticaNeueLTStd Thin Italic

275 HelveticaNeueLTStd UltraLight 
275 HelveticaNeueLTStd UltraLight Condensed 
275 HelveticaNeueLTStd UltraLight Condensed Oblique 
275 HelveticaNeueLTStd UltraLight Extended 
275 HelveticaNeueLTStd UltraLight Extended Oblique 
275 HelveticaNeueLTStd UltraLight Italic 

300 HelveticaNeueLTStd Light 
300 HelveticaNeueLTStd Light Condensed 
300 HelveticaNeueLTStd Light Condensed Oblique 
300 HelveticaNeueLTStd Light Extended 
300 HelveticaNeueLTStd Light Extended Oblique 
300 HelveticaNeueLTStd Light Italic 

400 HelveticaNeueLTStd Condensed 
400 HelveticaNeueLTStd Condensed Oblique 
400 HelveticaNeueLTStd Extended 
400 HelveticaNeueLTStd Extended Oblique 
400 HelveticaNeueLTStd Italic 
400 HelveticaNeueLTStd Roman

500 HelveticaNeueLTStd Medium 
500 HelveticaNeueLTStd Medium Condensed 
500 HelveticaNeueLTStd Medium Condensed Oblique 
500 HelveticaNeueLTStd Medium Extended 
500 HelveticaNeueLTStd Medium Extended Oblique 
500 HelveticaNeueLTStd Medium Italic 

700 HelveticaNeueLTStd Bold 
700 HelveticaNeueLTStd Bold Condensed 
700 HelveticaNeueLTStd Bold Condensed Oblique 
700 HelveticaNeueLTStd Bold Extended 
700 HelveticaNeueLTStd Bold Extended Oblique 
700 HelveticaNeueLTStd Bold Italic 
700 HelveticaNeueLTStd Bold Outline

750 HelveticaNeueLTStd Heavy 
750 HelveticaNeueLTStd Heavy Condensed 
750 HelveticaNeueLTStd Heavy Condensed Oblique 
750 HelveticaNeueLTStd Heavy Extended 
750 HelveticaNeueLTStd Heavy Extended Oblique 
750 HelveticaNeueLTStd Heavy Italic 

900 HelveticaNeueLTStd Black 
900 HelveticaNeueLTStd Black Condensed 
900 HelveticaNeueLTStd Black Condensed Oblique 
900 HelveticaNeueLTStd Black Extended 
900 HelveticaNeueLTStd Black Extended Oblique 
900 HelveticaNeueLTStd Black Italic 

950 HelveticaNeueLTStd ExtraBlack Condensed 
950 HelveticaNeueLTStd ExtraBlack Condensed Oblique 
Received on Tuesday, 19 May 2009 05:03:59 GMT

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