font-size starting size

[James Moe]

Hello,
I just joined this group and saw the discussion "What do you think of
resizing 1em to 10px?" I am somewhat confused by what y'all think should be
used as a reference size.
I was surprised that someone actually suggested ems as a reference. Ems
are relative to a selected point size, the width in points of a capital M.
If no point size is given, what size does an em become? The browser
obviously must decide.
Also setting the body text to 62.5% is, well, stupid. % of what? I should
*assume* 16 pixels? Bad thinking. And not my experience with browsers.

Using pixels does not scale very well at all. Text look quite large on a
17" 800x600 monitor, and quite small on a 20" 1600x1200 or 17" 1400x1050.
Our site recently changed from using hard-coded pixel settings to
assigning a default body text size in points and using % to set the other
sizes up or down. It has a more consistent look that way on displays of
different physical dimensions and resolutions.
I used "font-size=11pt" to define the reference size (which on my display
here is about 16 pixels). It is, of course, not very exact; it depends on
the browser and the display system to decide on what represents 1 point
(1/72 inch).

So after all that.... What is considered good practice for the base font
size?

--
jmm dash list at sohnen-moe dot com
(Remove .TRSPAMTR for email)

[Jukka K. Korpela]

James Moe <jm***************@sohnen-moe.com> wrote:

I just joined this group
Welcome. Now please read the fine FAQs.
Ems
are relative to a selected point size, the width in points of a
capital M.
You're fundamentally wrong. The em unit denotes the size of the font,
which has no defined relationship with any width.
If no point size is given, what size does an em become?
Read the FAQ.
The browser obviously must decide.
No, the user.
Also setting the body text to 62.5% is, well, stupid.
Of course.
I used "font-size=11pt" to define the reference size

And you got it ignored, right? Or did you use a broken browser?
--
Yucca, http://www.cs.tut.fi/~jkorpela/

[Neal]

On 4 Jun 2004 22:53:07 GMT, James Moe <jm***************@sohnen-moe.com>
wrote:

Ems are relative to a selected point size, the width in points of a
capital M. If no point size is given, what size does an em become? The
browser obviously must decide.
The "em" in CSS is not identcal to the print em. It is the default size of
a typical character after any inhereted adjustments. 1em is equivalent to
100%.

Ex. p {font-size:1.5em} means the p element text will be 150% of the
default.

However: body {font-size: 110%} p {font-size: 0.911em} means the p is back
to 100% or so.
Also setting the body text to 62.5% is, well, stupid. % of what?
Of whatever the user has set his preferred font size in the browser, or
the default size if it hasn't been set.
I should *assume* 16 pixels? Bad thinking. And not my experience with
browsers.
I agree. Assuming a particular pixel size is unwise.
So after all that.... What is considered good practice for the base
font size?

Nothing set at all, or use 100% or larger in the body element. This lets
the browser render the text at the size the user prefers, if he has set a
preference, or at the default setting, which that user should be quite
used to.

[Jukka K. Korpela]

Neal <ne*****@yahoo.com> wrote:

The "em" in CSS is not identcal to the print em.
It is the same concept: the size of the font.
It is the default
size of a typical character after any inhereted adjustments.

I wonder where all this misunderstandings about em stem from. The height
of a typical character is _much_ smaller than em, and the widths of
characters naturally vary, and they too are typically _much_ smaller than
em. The em unit does not denote any dimension of any specific character,
or any average dimension of characters.

--
Yucca, http://www.cs.tut.fi/~jkorpela/

[Wolfgang Wildeblood]

James Moe <jm***************@sohnen-moe.com> wrote:

Hello,
I just joined this group and saw the discussion "What do you think of
resizing 1em to 10px?" I am somewhat confused by what y'all think should be
used as a reference size.
[Musings snipped.]
So after all that.... What is considered good practice for the base font
size?

Secret users business. It is not necessary to specify a base font size
in an author stylesheet because the base font size is a *USER
SETTING*. I set it on my browser and you don't worry about it. I've
done all the worrying for you.

Don't give it another thought, it's all been taken care of. Consider
this:

sky {background-color: blue}

Why would you bother - it's already taken care of? You wouldn't give
it a first, let alone second, thought. Same with my browser settings -
don't give it a second thought.

Some alternative theories about the colour of the sky:

http://groups.google.com/groups?q=g:...hc45%404ax.com

http://groups.google.com/groups?hl=e...E8%40yahoo.com

--

[Steve Pugh]

James Moe <jm***************@sohnen-moe.com> wrote:

I was surprised that someone actually suggested ems as a reference. Ems
are relative to a selected point size, the width in points of a capital M.
You're a few centuries out of date. In modern typography the em is the
height of the font, which may or may not be the width of the capital M
(if such a letter exists in the font in question) in any given font.
If no point size is given, what size does an em become? The browser
obviously must decide.
When defining font-sizes the em is the size of the parent element's
font. Ultimately the root element has a font size set by the browser's
configuration. This is the size that the user has chosen (or chosen to
leave at the factory setting).
Also setting the body text to 62.5% is, well, stupid. % of what?
Yes it is stupid, because that's only 62.5% of the users chosen
default font size.
I should *assume* 16 pixels?
You might assume that. Other people would more correctly assume that
it would be 62.5% of the browser's default font size, of which 16px is
a common but not universal value.
Using pixels does not scale very well at all.
True. Beacuse browsers do not interpret the CSS spec correctly with
regard to the px element.

There's also the problem that Windows IE does not allow users to
easily resize text sized in px.
Our site recently changed from using hard-coded pixel settings to
assigning a default body text size in points and using % to set the other
sizes up or down. It has a more consistent look that way on displays of
different physical dimensions and resolutions.
But pt relate directly to real world physical measurements. So your
body size set at 11pt should be 11/72 of an inch regardless of all
other factors. Did you put a ruler up to the screen and measure it?
Did any browser get it right?

What happens when teh page is projected onto a wall screen? Is the
text still 11pt? How can anyone read 11pt text from across the room?

And there's also the problem that Windows IE does not allow users to
easily resize text sized in pt.
I used "font-size=11pt" to define the reference size
Which should be ignored as it's totally incorrect syntax.
(which on my display here is about 16 pixels).
Which may be because 16 pixels is the default and the browser is
ignoring you incorrect syntax? Or it may be that your screen has a
resolution of 105 pixels per inch. Or it may be that your browser is
following typical practice and assuming a resolution of 96dpi and thus
11pt is 14.7 pixels (falls within "about 16 pixels") regardless of the
actual resultion.
It is, of course, not very exact; it depends on
the browser and the display system to decide on what represents 1 point
(1/72 inch).
Most modern browsers assume 96dpi and so 12pt = 16px and everything
flows from that. Some browsers assume other resolutions, e.g. if you
set Windows to use Large Fonts is assumes 120dpi and hence your 11pt
would be 18.3 pixels.
So after all that.... What is considered good practice for the base font
size?

Whatever the user has configured their browser to use.

Steve

--
"My theories appal you, my heresies outrage you,
I never answer letters and you don't like my tie." - The Doctor

Steve Pugh <st***@pugh.net> <http://steve.pugh.net/>

[Barry Pearson]

Steve Pugh wrote:

James Moe <jm***************@sohnen-moe.com> wrote:

[snip]

Also setting the body text to 62.5% is, well, stupid. % of what?

Yes it is stupid, because that's only 62.5% of the users chosen
default font size.

I should *assume* 16 pixels?

You might assume that. Other people would more correctly assume that
it would be 62.5% of the browser's default font size, of which 16px is
a common but not universal value.

[snip]

It is only 62.5% of the browser's default font size if the font-family is left
as the default. If the font-family is specified when the 62.5% is specified,
the practical percentage of the user's default font cannot be determined.
Because it is unknown what the subjective & objective size of the specified
font is compared with that of the user's default font.

(I don't advocate 62.5%, which is new to me! But I observe that, on my system,
13px Arial & 80% Arial are subjectively & objectively about the same size as
my default font, which is 16px Times New Roman. This requires a somewhat
narrow measure of objective size - in fact the 13px Arial width of some text I
used for analysis was 97% of the width of the 16px Times New Roman, and
certain letters such as lower-case "o" were the same size, as 16px TNR, at
somewhere between 13px & 14px Arial).

--
Barry Pearson
http://www.Barry.Pearson.name/photography/
http://www.BirdsAndAnimals.info/
http://www.ChildSupportAnalysis.co.uk/

[Jan Roland Eriksson]

On Sat, 5 Jun 2004 05:37:20 +0000 (UTC), "Jukka K. Korpela"
<jk******@cs.tut.fi> wrote:

Neal <ne*****@yahoo.com> wrote:

The "em" in CSS is not identcal to the print em.

It is the same concept: the size of the font. It is the default
size of a typical character after any inhereted adjustments.

I wonder where all this misunderstandings about em stem from.
Yea; Me to gets astonished at some of the interpretations that pops up
every now and then.
The height of a typical character is _much_ smaller than em

Well; to the naked eye yes, but...

The majority of fonts designed within the previous millennium are
designed to fit on a lead block destined to be set in a printing frame.

In order to facilitate easy typesetting, all lead blocks used in a
printing frame has to be of the same height (for western alphabets that
is).

Following that, the minimum height of a lead block, intended for use in
traditional typesetting, must be as high as required to "house" any one
single character in the font in use when each and every character in
that font is placed on a common baseline.

So the net result is that 1em becomes equal to the height of the lead
block required to "house" any one character in any given font design.

Note; this includes height to "house" character decenders just as well
as diacritical marks, should they be designed parts of the font at hand.

The definition of one 'em' in CSS1 is derived from traditional
typesetting and I have at one time been in live "person to person"
discussion with Haakon on this subject and there is no doubt that the em
definition in CSS1 has its roots in the minimum required height of a
lead block, as used in traditional typesetting for prints.

Further; it can be empirically proven that font designers as early as
Claude Garamond (hundreds of years back) was thinking along the same
line.

The "Plantin Moretus Museum" in Antwerp, Belgium, has a large set of
Claude Garamond's original design work in storage. One very specific
item there is the Garamond definition of what we would call an "em dash"
which just "happens" to be designed to fit the full width of a _square_
lead block with a block height equal to all other block character casts
available.

Naturally we can also find an "en-dash" in the Garamond font and from
the best judgment I was able to make on site, the Garamond en-dash is
very close to half the width of the em-dash.

Given the fact that there is European historical roots available for the
definition of one 'em' I would, provocatively, move on to say that any
saying to the effect that "1em is equal to the width of letter 'm' or
'M'" is nothing but Bullshit of Anglo-Saxon origin :-)

--
All the best...
Rex

P.S. Why did Knuth fall for that "em is letter 'm' width" thingy in
LaTex?

[Tim]

On Sat, 05 Jun 2004 14:00:33 +0200,
Jan Roland Eriksson <jr****@newsguy.com> posted:

Given the fact that there is European historical roots available for the
definition of one 'em' I would, provocatively, move on to say that any
saying to the effect that "1em is equal to the width of letter 'm' or
'M'" is nothing but Bullshit of Anglo-Saxon origin :-)

The only definition that I ever had much faith in was saying that the em
was the "size" of the "M" (not the width, not the height, but the size of
the whole thing, taking into account all aspects of printing the letter
amongst other letters (including ascenders, descenders, the usual space
around it, etc.).

On every browser that I've played with, it's impossible to correlate the
size of the em to any of the characters that you can display (e.g. do
something that's 12 ems big, then try and compare that to any 12 characters
in a row or column), and it's made doubly worse by the limited applications
of what CSS can do with it.

For instance, if I was to make a box (e.g. a div) have margins around it so
it was smaller than the surrounding body, and used ems to set the margins,
they seem to be based on the size of characters inside the div, yet I'd
rather be able to set the margin sized based on the surrounding characters
on the page. The worst example being trying to do something like a big
bold warning - it gets a huge margin around it.

--
If you insist on e-mailing me, use the reply-to address (it's real but
temporary). But please reply to the group, like you're supposed to.

This message was sent without a virus, please delete some files yourself.

[James Moe]

Jukka K. Korpela wrote:

James Moe <jm***************@sohnen-moe.com> wrote:

I just joined this group Welcome. Now please read the fine FAQs.

And the link is?: ___________________________

Ems are relative to a selected point size, the width in points of a
capital M.
You're fundamentally wrong. The em unit denotes the size of the font,
which has no defined relationship with any width.

You, and others, have noted the poor phrasing. An em (aka: em square, em
box) is the default distance between baselines without extra leading.

If no point size is given, what size does an em become?

Read the FAQ.

(See above.)

The browser obviously must decide. No, the user.

Quite so. My mistake.
My confusion stemmed from forgetting this obvious fact: the user does
indeed set the base size.

I used "font-size=11pt" to define the reference size

And you got it ignored, right? Or did you use a broken browser?

A typo.
Just writing "Bzzt! Wrong!" is not helpful. I joined this group to learn
more about stylesheets and their use.
--
jmm dash list at sohnen-moe dot com
(Remove .TRSPAMTR for email)

[Jukka K. Korpela]

James Moe <jm***************@sohnen-moe.com> wrote:

Welcome. Now please read the fine FAQs.

And the link is?: ___________________________

You cannot miss it if you hang around. Actually, it is recommended
practice to read a group for some time, or at least check recent
discussions via Google, before posting.

I used "font-size=11pt" to define the reference size

And you got it ignored, right? Or did you use a broken browser?

A typo.
Just writing "Bzzt! Wrong!" is not helpful.

Oh, it is. Exactness is notations is one thing that you need to learn
when learning CSS. It's no use telling you each mistake; you need to
learn to detect them yourself, by using a CSS checker (and reading
tutorials and specifications).

--
Yucca, http://www.cs.tut.fi/~jkorpela/

[James Moe]

Steve Pugh wrote:

But pt relate directly to real world physical measurements. So your
body size set at 11pt should be 11/72 of an inch regardless of all
other factors. Did you put a ruler up to the screen and measure it?
Did any browser get it right?
What happens when teh page is projected onto a wall screen? Is the
text still 11pt? How can anyone read 11pt text from across the room?
What happens when a slide with 24pt text is projected?
And there's also the problem that Windows IE does not allow users to
easily resize text sized in pt.

I used "font-size=11pt" to define the reference size
Which should be ignored as it's totally incorrect syntax.

A typo. "Bzzt! Wrong!" is not helpful.

So after all that.... What is considered good practice for the base font
size?

Whatever the user has configured their browser to use.

Thank you.

--
jmm dash list at sohnen-moe dot com
(Remove .TRSPAMTR for email)

[Steve Pugh]

James Moe <jm***************@sohnen-moe.com> wrote:

Steve Pugh wrote:

What happens when the page is projected onto a wall screen? Is the
text still 11pt? How can anyone read 11pt text from across the room?

What happens when a slide with 24pt text is projected?

If the slide is projected using a CSS-based technology then the
resulting text on the screen should be 24/72 of an inch high. Nothing
else is correct.

If you're talking about a real photographic slide then does it really
have 24pt text on it? You wouldn't get many 24/72 inch high letters on
a typical photographic slide would you?

I used "font-size=11pt" to define the reference size

Which should be ignored as it's totally incorrect syntax.

A typo. "Bzzt! Wrong!" is not helpful.

How were we to know that it's a typo? That exact same mistake is seen
quite frequently in posts from people asking why their styles don't
work. If you can't be bothered to post correct code why should we be
bothered to second guess what you meant to post?

Steve

--
"My theories appal you, my heresies outrage you,
I never answer letters and you don't like my tie." - The Doctor

Steve Pugh <st***@pugh.net> <http://steve.pugh.net/>

[Steve Pugh]

James Moe <jm***************@sohnen-moe.com> wrote:

Jukka K. Korpela wrote:

James Moe <jm***************@sohnen-moe.com> wrote:

Ems are relative to a selected point size, the width in points of a
capital M.

You're fundamentally wrong. The em unit denotes the size of the font,
which has no defined relationship with any width.

You, and others, have noted the poor phrasing. An em (aka: em square, em
box) is the default distance between baselines without extra leading.

Not in CSS it isn't. The distance between baselines is given by the
line-height property, which by default in many browsers is about
1.15em. An em is the height of the font, no more, no less. And an
em-quad is the square unit that has sides of 1em length.

Steve

--
"My theories appal you, my heresies outrage you,
I never answer letters and you don't like my tie." - The Doctor

Steve Pugh <st***@pugh.net> <http://steve.pugh.net/>

[Alan J. Flavell]

On Sat, 5 Jun 2004, Steve Pugh wrote:

Not in CSS it isn't. The distance between baselines is given by the
line-height property, which by default in many browsers is about
1.15em. An em is the height of the font, no more, no less.

Sure, but that begs the question as to what represents the "height of
the font" in CSS. On the web you don't get a lump of leaded type to
pick up and examine; the "height of a font" stands in a somewhat
tenuous relationship to the size of the glyphs, and that relationship
is different for different font faces. It's no wonder that folks get
confused, when there's nothing physical to get hold of.

See how difficult it is for folks to grasp that the pt unit defines an
absolute physical length, just as much as the cm or inch does. They
imagine they can have some kind of elastic scaled pt unit which does
whatever they want it to.

[Dr John Stockton]

JRS: In article <Xn*****************************@193.229.0.31>, seen in
news:comp.infosystems.www.authoring.stylesheets, Jukka K. Korpela
<jk******@cs.tut.fi> posted at Fri, 4 Jun 2004 23:05:54 :

James Moe <jm***************@sohnen-moe.com> wrote:

I just joined this group

Welcome. Now please read the fine FAQs.

But which ones? None are regularly posted to this newsgroup, there
seems to be no frequent regular posting citing them, the regular users
do not cite them in their sigs, and a Google search can be misleading.

I suppose that you mean
http://css.nu/faq/ciwas-mFAQ.html
http://css.nu/faq/ciwas-aFAQ.html
(linked via sig line 3), but ICBW.

--
© John Stockton, Surrey, UK. ?@merlyn.demon.co.uk Turnpike v4.00 IE 4 ©
<URL:http://jibbering.com/faq/> Jim Ley's FAQ for news:comp.lang.javascript
<URL:http://www.merlyn.demon.co.uk/js-index.htm> jscr maths, dates, sources.
<URL:http://www.merlyn.demon.co.uk/> TP/BP/Delphi/jscr/&c, FAQ items, links.

[Dr John Stockton]

JRS: In article <ef********************************@4ax.com>, seen in
news:comp.infosystems.www.authoring.stylesheets, Jan Roland Eriksson
<jr****@newsguy.com> posted at Sat, 5 Jun 2004 14:00:33 :

So the net result is that 1em becomes equal to the height of the lead
block required to "house" any one character in any given font design.
Logical.
... Naturally we can also find an "en-dash" in the Garamond font and from
the best judgment I was able to make on site, the Garamond en-dash is
very close to half the width of the em-dash.

Given the fact that there is European historical roots available for the
definition of one 'em' I would, provocatively, move on to say that any
saying to the effect that "1em is equal to the width of letter 'm' or
'M'" is nothing but Bullshit of Anglo-Saxon origin :-)

However, the "lead block" height of a font is not visible on the paper,
unless the leading is known to be zero (ISTM difficult in traditional
technology) ; and in an ordinary printer's font (for the English
alphabet) the width of a printed M - or perhaps the distance between the
centres of two normally-packed Ms - is observable and of similar size.
Hence "em" was a convenient name for the unit (and "en" for about half
of that).

So, while an em may not be defined as the width of an M, it remains true
that the width of a normal M (or separation of a pair) is either an em
or close to it - in much the same way as an English mile is close to
1.609 km or 1609.344 m, although AIUI neither is the fundamental
definition.

Of course, "em", as found in English dictionaries, is an English word;
and the authors of English dictionaries (possibly neglecting some of
those who were Scots) were Anglo-Saxons by ancestry - and thus had a
perfect right and duty to describe our language, with scornful disregard
for those lesser realms which have land-borders with further realms.

--
© John Stockton, Surrey, UK. ?@merlyn.demon.co.uk Turnpike v4.00 MIME. ©
<URL:http://www.merlyn.demon.co.uk/> TP/BP/Delphi/&c., FAQqy topics & links;
<URL:http://www.merlyn.demon.co.uk/clpb-faq.txt> RAH Prins : c.l.p.b mFAQ;
<URL:ftp://garbo.uwasa.fi/pc/link/tsfaqp.zip> Timo Salmi's Turbo Pascal FAQ.

[Jukka K. Korpela]

Dr John Stockton <sp**@merlyn.demon.co.uk> wrote:

So, while an em may not be defined as the width of an M, it remains
true that the width of a normal M (or separation of a pair) is either
an em or close to it - in much the same way as an English mile is
close to 1.609 km or 1609.344 m, although AIUI neither is the
fundamental definition.

No, it does not. The width of M varies, see e.g.
http://www.cs.tut.fi/cgi-bin/run/~jk...ode=MMMMMMMMMM
to see how much variation there is - the page contains a string of M's
in different fonts, _with the same font size_.

The relationship with the em unit and the Latin letter M is historical
only.

--
Yucca, http://www.cs.tut.fi/~jkorpela/

[Evertjan.]

Jukka K. Korpela wrote on 06 jun 2004 in
comp.infosystems.www.authoring.stylesheets:

No, it does not. The width of M varies, see e.g.
http://www.cs.tut.fi/cgi-bin/run/~jk...ode=MMMMMMMMMM
to see how much variation there is - the page contains a string of M's
in different fonts, _with the same font size_.

However, this can be correctd by changing the fontsize by javascript

<http://devrijehuisarts.org/test/stringwidthfonttest.asp?code=qwerty+asdfg>

The loops take some time, but the result gives equal width strings.

--
Evertjan.
The Netherlands.
(Please change the x'es to dots in my emailaddress)

[Steve Pugh]

"Evertjan." <ex**************@interxnl.net> wrote:

Jukka K. Korpela wrote on 06 jun 2004 in
comp.infosystems.www.authoring.stylesheets:

No, it does not. The width of M varies, see e.g.
http://www.cs.tut.fi/cgi-bin/run/~jk...ode=MMMMMMMMMM
to see how much variation there is - the page contains a string of M's
in different fonts, _with the same font size_.
However, this can be correctd by changing the fontsize by javascript

Isn't 'corrected' is a bit strong as nothing was 'incorrect' to start
with?
<http://devrijehuisarts.org/test/stringwidthfonttest.asp?code=qwerty+asdfg>

The loops take some time, but the result gives equal width strings.

Only works in IE because it relies on IE's bogus handling of overflow.

Steve

--
"My theories appal you, my heresies outrage you,
I never answer letters and you don't like my tie." - The Doctor

Steve Pugh <st***@pugh.net> <http://steve.pugh.net/>

[Evertjan.]

Steve Pugh wrote on 06 jun 2004 in
comp.infosystems.www.authoring.stylesheets:

"Evertjan." <ex**************@interxnl.net> wrote:

Jukka K. Korpela wrote on 06 jun 2004 in
comp.infosystems.www.authoring.stylesheets:

No, it does not. The width of M varies, see e.g.
http://www.cs.tut.fi/cgi-bin/run/~jk...ode=MMMMMMMMMM
to see how much variation there is - the page contains a string of
M's in different fonts, _with the same font size_.

However, this can be correctd by changing the fontsize by javascript

Isn't 'corrected' is a bit strong as nothing was 'incorrect' to start
with?

<http://devrijehuisarts.org/test/stri...code=qwerty+as
dfg>

The loops take some time, but the result gives equal width strings.

Only works in IE because it relies on IE's bogus handling of overflow.

I do not suggest to use this in a real life web page situation, but one
could adapt the specific string font-sizes in a static page after
measuring it this way.

btw: sofar, only you with Opera751, IE6 and Gecko
and someone else with Netscape7.2 have looked at my page.

tnx for testing.

--
Evertjan.
The Netherlands.
(Please change the x'es to dots in my emailaddress)

[Jan Roland Eriksson]

On Sat, 5 Jun 2004 18:16:11 +0100, Dr John Stockton
<sp**@merlyn.demon.co.uk> wrote:

JRS: In article <ef********************************@4ax.com>, seen in
news:comp.infosystems.www.authoring.stylesheets, Jan Roland Eriksson
<jr****@newsguy.com> posted at Sat, 5 Jun 2004 14:00:33 :
[...]

Given the fact that there is European historical roots available for the
definition of one 'em' I would, provocatively, move on to say that any
saying to the effect that "1em is equal to the width of letter 'm' or
'M'" is nothing but Bullshit of Anglo-Saxon origin :-)

[...]
So, while an em may not be defined as the width of an M, it remains true
that the width of a normal M (or separation of a pair) is either an em
or close to it...
Not so;

You are probably much closer than I am to make a real comparison between
an early 1930 edition of the Times and compare it to a late 1930 edition
of the same newspaper. What happened between these two editions is that
Stanley Morrison made a re-cut of the original "Times Roman" type into
what now is our (in)famous "Times New Roman" type.

There is a definite difference in character compactness between these
two types (approx. 15% more printed information within a given space for
'TNR' as compared to 'TR')

The width of the letter 'M' suffered approx. the same degree of mangling
into 'TNR' as other characters did, hence it now has even less
resemblance (if it ever had one) to '1em'.
Of course, "em", as found in English dictionaries, is an English word;
Never the less its real origin is French of course.
and the authors of English dictionaries (possibly neglecting some of
those who were Scots) were Anglo-Saxons by ancestry - and thus had a
perfect right and duty to describe our language...

Sure; My 1965 edition of "Oxford Illustrated" manage to make a real mess
of its description of the 'em' unit.

em (noun)

1. Name of letter 'M'

(hmm, maybe plausible)

2.(printing) Measure equivalent to 12 points
or approx. 1/6 inch;

(that part of the description is just laughable,
and it goes on to say...)

also the square of any size of type, thus [ ].

(where my use of the two square brackets is an attempt
to illustrate the real square that is printed after the
word 'thus', a square that does not have room for a
character with a descender as in e.g. the letter 'Q' or 'p'.
following that it can not be said to represent the
"square of any size of type" as claimed.)

So it seems to me that the "Oxford Illustrated" is an "Anglo-Saxon"
product, produced just as you say; it's in real error too which does not
make it any better.

http://css.nu/articles/typograph1-en.html

--
Rex