ALT background materials
[1]
On the question of authoring style,
there's some very instructive early discussion in the
Style
Guide for Online Hypertext at
the W3C, with particular
reference to Don't
format for a particular browser and Avoid
talking about the Mechanics.
After all, the author of a book does not normally try to
tell the reader how to read it, what light to read it in,
how to use the fold-out insert etc. unless there were some very
special reason to do so.
You'd assume they already understand how
to do that, or have the freedom to choose for themselves, wouldn't you?
So, I would ask you to kindly not patronise your readers
by implying that they don't know how to use their own WWW browser.
While it's true that at a time of explosive growth of the WWW, many
readers will be newcomers and maybe not fully familiar with their
browsers yet, your article on wild mushrooms isn't going to be improved
by turning it into yet another browser-use tutorial. If there's some
special requirement on your page, then I'd recommend you politely
suggest your users visit a tutorial on the use of their particular
browser.
Bear in mind that they might not be using the same browser/platform
that you use, and if you try to tell them how to use your
browser, it's quite possible that you will confuse them.
Explanation and Disclaimer
I make no claim here to be offering the one and only correct
answer, or even necessarily the best answer, to any particular situation
discussed. In each case, there will be quite a range of
solutions that would fulfil the requirements of getting
the desired message to readers of all kinds. There will also
be a wide range of purported solutions (as seen repeatedly on
the WWW) that quite unnecessarily fail in a
significant range of browsing situations: no-one can reasonably object
in a situation where the nature of the material itself
precludes it being available - what is being objected to here is
material that is inherently textual in nature being pointlessly made
inaccessible.
My chief aim has been to bring the subject into the open; to
provoke further reasoned discussion; and to address the many
incomprehensible ALT texts that I am seeing on the WWW.
In doing so, I hope also to demonstrate that the often repeated
claim that "authoring also for text-only users would cost us an
unreasonable additional effort which we cannot afford" is a
mistake: this claim seems plausible only if you don't know
what it is that you are trying to say to your readers, and have
confused the presentation details (which in any case cannot be
closely controlled by writing HTML for the WWW) with
the content of your message.
[2]
I can't resist mentioning here that the HTML3.0 draft
recognized the shortcomings of the IMG tag by
introducing a new and much more versatile tag, FIG,
which was supported by one or two advanced browsers, though
not by the mass-market ones;
finally, the HTML4.0 recommendation offers a re-worked version
of that as the OBJECT.
However, within the scope of this note I am specifically dealing with
the appropriate use of the IMG tag.
Indeed, the OBJECT is still not well supported by browsers
at the time of writing.
[3]
Why would a reader be using a text mode browser?
a.k.a Why should I, as an author, bother with them?
There are many possible reasons.
If you, as an author, assume that you know the reason (for
example, if you assume that text mode is only used by people
with a low disposable income, and therefore of no interest
to you), then you will very likely exclude - and annoy - some
people that you really would like to have as customers,
even though you didn't realise it.
Apart from that, if you are making available some textual
information, then what logical reason could you have for fencing
it away behind an impenetrable thicket of graphics-only
material?
One of the most important readers of your WWW page is the
indexing robot: it is, in effect, blind, and cannot understand
your images. The ALT text is an excellent way to help the robot
and ensure that your page will be indexed appropriately.
Some authors seem to prefer spending lots of effort on composing
META tags for the indexers - which is a reasonable enough idea in
itself - but that produces no visible spinoff for your text-mode
human readers, whereas effort spent on your ALT texts produces
benefits for both kinds of "reader".
And there has been so much abuse of the META tags by some
web-page providers,
that certain indexers now ignore the META entirely, or
apply strict disqualification rules to avoid getting fooled by
that kind of trickery.
With 30Mio+ URLs on the WWW, you really don't stand much chance of
an interested reader finding your page by their own unaided efforts:
everything you can do to get it
indexed properly is giving you an extra chance to reach readers
who are specifically interested in what you have to offer them.
These are your "quality" visitors, each one far more valuable to you than
an army of readers who might stumble onto your URL while "surfing".
Food for Thought
1. In Europe, at least, the digital cellphone (GSM or DCS-1800) is now
a commonplace.
Increasingly, these digital cellphones are coming equipped with
a digital data socket, to which a more elaborate display, for
example a laptop or palmtop, can be connected, either for
display of SMS messages or for a fullscale dialup digital data path
to an Internet provider etc.
However, the data rate that is available is quite limited,
compared with a wire telephone, due to
the broadcast nature of the transmission path.
Within the defined transmission standards, it is inconceivable
that any large scale browsing of images is going to be
achieved with an access time that would be acceptable for
routine browsing.
2. In the Hitchhiker's Guide
to the Galaxy by Douglas
Adams, The Book is described as a handy device having
a display about four inches square, capable of displaying any
one of a million pages of information.
It's clear that The Book is conceived as a self-contained system,
as would be appropriate for the intergalactic traveller.
Here in the real world, we
have palmtops (e.g the Psion, the Newton) that are
getting better all the time; and we have digital cellphones, that
are getting hooked up to palmtops.
See for example the On-line with your Psion
page at Steve Litchfield's
3-Lib site.
So, something rather like The Book,
but giving access to not just a million pages of information
stored within it, but the 30million-plus (and still counting)
documents on the WWW.
This will only be practical for text, and simple graphics.
Those humungous images will definitely not be retrieved routinely:
this is a fundamental limitation of the transmission path, not
just a minor technical obstacle to be overcome.
In fact, subsequent to my writing this section, several
products consisting of a cellphone with integrated web browser, or
cellphone/palmtop combo, have appeared, e.g the Nokia 9000 series and
the Psion
5
3. The Speaking Machine - not only for the blind.
Busy executives might have a speaking machine read out stuff
to them while they are driving between business meetings.
Also dial-a-web-page telephone services etc.
4. Some sceptics on the WWW usenet groups, when an unusual
or futuristic presentation device is mooted, appear to
believe that they gain some benefit by deliberately shutting out
those unusual devices, rather than exploiting HTML's ability,
when used appropriately,
to put their information into every reader's browsing situation.
This shows a very narrow minded and short sighted view,
unworthy of the high principles of the
WWW.
Why "author for" a restricted reading situation, when HTML
(at least where textual material is concerned) enables you to
"author for" all reading situations?
The oft-repeated phrase about "target audience" refers to those
people to whom you are aiming your "topic of discourse": applying
yet another layer of selectivity according to their browsing situation
(except where the content by its very nature compels you to)
seems to be a misunderstanding of what "target audience"
or "target readership" is about.
Even 0.01% of internet users is still a significant number
of individuals, especially if they just happened to be the
people who might be interested in your product: how can you be
sure they're not?
Truly it has been said that many WWW pages have
been
Optimised
for arguing with customers
,
and things seem to be getting worse rather than better.
Some specifics
Anyway, here's my very incomplete list of why readers might choose to
use a text-only browser, or a graphics browser with auto image loading
turned off.
- Poor network response means they aren't willing to wait for
graphics to come down, especially as they suspect that the author
only included them as trivial decoration
- They're out in the field, using a laptop or palmtop and a dial
up modem; its graphics display may be poor, quite apart from
modem speed.
- Palmtop and digital cellphone. Cutting-edge technology,
folks, but the data rate is strictly limited, and call charges are
high. These are people with lots of disposable income, but in
this situation they aren't going to wait for the graphics.
- Ocean yacht with satellite link... (hey, some chance on my salary!)
- Reader already knows that the information they want is
inherently textual, and aren't willing, even on a high speed
network, to load images that they know they don't need.
These are serious readers, folks. How do you know they won't
buy your product?
- Blind readers (using e.g a text mode browser fed into a
speaking machine, or a purpose-designed speaking WWW browser
such as pwWebSpeak).
- Readers who like the speed and HTML coverage that's
offered by Lynx or by emacs-w3.
- Low-income groups using cast-offs like VT100 terminals and
old lowspeed modems. Or in developing countries with inadequate
telecom infrastructure (see
Abigail's
dream...).
- There are top-of-the-range workstations in the office - but
a cast-off laptop kept in the car for occasional access while out
and about.
- The
"Web-on-Call(TM) Voice
Browser" previously mentioned here as a product permitting
textual WWW pages to be read out over the telephone, is no
longer evident on its web site; it wasn't the only such offering
that I have seen, but sorry, I don't have a URL to hand just now.
- I'm sure there are many more reasons I didn't think of.
- Not forgetting those indexing robots...
Right, you clever authors that say text mode readers aren't
worth bothering about: what was the common factor in all those
users, apart from the fact that they use text mode (whether
from choice or from necessity)? I reckon there wasn't one.
Just because you think you know the "profile" of your target
audience, does not mean that they will all of them fit that
profile, all of the time.
When you advertise in the wrong magazine, you merely miss some
of your potential customers: no active harm is done.
When you offer WWW readers something which, it turns out, they
cannot read because it's been designed for a limited range of
platforms, you have been actively rude
to a potential customer.
You only have to annoy them once,
to send them to your competitors. Just one disgruntled
customer can generate a lot of negative advertising, and
lose you other potential customers.
[4]
Blind readers
I have to confess to having rather little experience of writing
WWW documents specifically for blind readers.
The issues are a hot topic at the Web
Accessibility Initiative area at W3C.
Frankly, many of the pages that I see on the WWW are so obviously
in need of a degree of care and attention that would help all
text-mode readers, and so often I have received the response from
unsympathetic authors who refuse to spend their time adjusting
their pages for what they see as a small minority group; therefore I am
concentrating on techniques that seem to be beneficial for all
text mode readers, and by implication also for blind readers as
well as for indexing robots, rather than convincing such sceptics
to spend additional time enhancing their pages specifically for
blind readers.
I hope my intentions in proceeding this way will not be
misunderstood: I applaud those authors who would additionally
like to take the time to make their documents even more accessible, and
who are willing to follow appropriate guidelines.
Note that in HTML4.0 there are three or four attributes available
for their respective purposes (I'm paraphrasing the HTML4.0
recommendation):
- The ALT attribute of the IMG, for alternative text,
- The TITLE attribute of the IMG, for supplementary information
relevant to the IMG,
- The LONGDESC attribute of the IMG, for the URL of a full
text description of the image,
- The TITLE attribute of the enclosing A anchor link, if any, for
supplementary information relevant to the link.
How best to use these mechanisms is still under active discussion in
detail, but we can see that there is even less reason now to use
the ALT attribute for mere descriptions of the image, in general.
For legacy browsers, the forerunner of the LONGDESC attribute
is the
D-link, pioneered by WGBH.
[5]
The colour of ALT texts
I received an interesting email from someone who was attempting,
unsuccessfully, to use
FONT COLOR to get their ALT texts to contrast properly against their
dark-ish background.
It's been my experience that the ALT text shows up in the same colour
as is specified in the TEXT attribute of the BODY tag, or in some
browsers if the image is a link then it will use the LINK or VLINK
colour as appropriate.
FONT COLOR is dangerous in Netscape anyway, because it cannot be
disabled by choosing the "use my colors" option. Thus, the reader who
is in a difficult browsing situation and trying to make matters better
by controlling the colours themself, will get the author's chosen FONT
COLOR displayed against the reader's choice of background. In some
cases this makes text totally invisible. This issue is discussed in
more detail in Warren Steel's FONT
rant.
MSIE and Opera don't have this bug: when they are set to use the
reader's colour scheme, it overrides FONT COLOR as well as the other
colour attributes.
Because of Netscape, I would recommend avoiding FONT COLOR whenever
possible, and only using it to specify colours that are expected to be
an effective contrast against any plausible background colour. Use of
the colour attributes of the BODY tag, by comparison, is harmless,
because all browsers can override it when the reader finds it
necessary. Of course, if you use a background image then its colour
needs to be consonant with your BGCOLOR attribute.
I recommended my correspondent to set the basic colour choices for
their page in the BODY attributes only. In my experience this gives
good results with the ALT texts on a good range of browsers.
The contents of this article were originally published at http://ppewww.ph.gla.ac.uk/%7Eflavell/alt/alt-more.html.
Original
materials © Copyright 1994 - 1999 A.J.Flavell
& Glasgow University
