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Thread: Image replacement and WCAG2.0

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From: Paul Collins
Date: Wed, Nov 11 2009 4:15AM
Subject: Image replacement and WCAG2.0
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Hi all,

My colleague has asked me if you can use graphical headings in WCAG2.0, so I guess by that he means using and <IMG> tag with an ALT attribute. I've tried to find information on this and can't see anything.

I beleive there was nothing specific about this in WCAG1.0, but there was always the issue that a graphical heading cannot be enlarged (apart from within a few modern browsers that have ZOOM)

So, I was wondering if anyone can answer the following for me:

- Would it be OK to use a graphical heading and satisfy level AA of WCAG 2.0
- Does anyone know the specific guideline that points to this?

Thanks for any help
Paul Collins

From: Simius Puer
Date: Wed, Nov 11 2009 5:00AM
Subject: Re: Image replacement and WCAG2.0
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Technically I don't think there is any reason in the WCAG 2 that you
*must*not do this. Most modern browser now re-size the whole page,
not just the
text so that is less of an issue.

As long as you meet the following guidelines then you should be okay - at
least on paper.

Guideline 1.1 : Provide text alternatives for all non-text content
- as you suggest, alt tags should be sufficient
Guideline 1.3 : Ensure that information and structure can be separated from
presentation
- again, if you use the correct semantic mark-up then the structure is
there
Guideline 1.4 : Make it easy to distinguish foreground information from its
background
- you should always check foreground/background contrast but this one is
often over-looked by people using images of text rather than the real thing
(also the guideline regarding non-flashing content).

As to whether it is a god idea or not is another matter.

Argument for:

- it allows you to closer control over the exact design.

Arguments against:

- You are removing the users ability to over-ride foreground/background
colours
- accessibility issues: not strictly a fail as such, but it won't
necessarily be well received
- Zooming the screen may have greater undesirable effects
- design issue: test carefully using a wide-range of browser if you use
this route...they don't all "magnify" the same way
- Putting text from headers into alt text reduces its weighting in search
engines
- SEO issues: your SERPs (search engine page results) will suffer
- If you use images for headers then you are increasing the number of
page elements + document size
- usability issue: increasing download time and page rendering time -
potentially upsetting visitors on slower connections.

Unless there is a very specific and compelling reason for using images in
the headers I'd suggest looking at CSS controlled text. A good CSS designer
can make text look pretty damn impressive without the need to resort to
using images.

Hope that helps

From: Steve Green
Date: Wed, Nov 11 2009 6:45AM
Subject: Re: Image replacement and WCAG2.0
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The use of images of text was specifically prohibited under WCAG 1.0
checkpoint 3.1 (AA).

Under WCAG 2.0 the requirement has been retained but it is a bit of a fudge.
Checkpoint 1.4.5 (which is AA) says:

"Images of Text: If the technologies being used can achieve the visual
presentation, text is used to convey information rather than images of text
except for the following:
Customizable: The image of text can be visually customized to the user's
requirements;
Essential: A particular presentation of text is essential to the information
being conveyed."

We interpret this as meaning that you can use images of text if the required
visual presentation (such as a specific font or an effect such as a dropped
shadow) cannot be achieved using HTML.

This is not permitted at AAA. Checkpoint 1.4.9 states "Images of text are
only used for pure decoration or where a particular presentation of text is
essential to the information being conveyed."


So the answer to your question is that you can meet WCAG 2.0 AA if you use
an image of text as long as the same visual effect cannot be achieved using
HTML and CSS. In my opinion this is unsatisfactory and WCAG 2.0 should have
prohibited this at AA not just at AAA.

Steve Green
Director
Test Partners Ltd


----------------------------------------------------------------------------
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From: = EMAIL ADDRESS REMOVED = on behalf of Paul Collins
Sent: Wed 11/11/2009 11:12
To: WebAIM Discussion List
Subject: [WebAIM] Image replacement and WCAG2.0


Hi all,

My colleague has asked me if you can use graphical headings in WCAG2.0, so I
guess by that he means using and <IMG> tag with an ALT attribute. I've tried
to find information on this and can't see anything.

I beleive there was nothing specific about this in WCAG1.0, but there was
always the issue that a graphical heading cannot be enlarged (apart from
within a few modern browsers that have ZOOM)

So, I was wondering if anyone can answer the following for me:

- Would it be OK to use a graphical heading and satisfy level AA of WCAG 2.0
- Does anyone know the specific guideline that points to this?

Thanks for any help
Paul Collins

From: Andrew Kirkpatrick
Date: Wed, Nov 11 2009 7:15AM
Subject: Re: Image replacement and WCAG2.0
← Previous message | Next message →

Related WCAG 2.0 technique: http://www.w3.org/TR/WCAG-TECHS/C30.html


Thanks,
AWK

Andrew Kirkpatrick

Senior Product Manager, Accessibility

Adobe Systems

= EMAIL ADDRESS REMOVED =


-----Original Message-----
From: = EMAIL ADDRESS REMOVED = [mailto: = EMAIL ADDRESS REMOVED = ] On Behalf Of Steve Green
Sent: Wednesday, November 11, 2009 8:43 AM
To: 'WebAIM Discussion List'
Subject: Re: [WebAIM] Image replacement and WCAG2.0

The use of images of text was specifically prohibited under WCAG 1.0
checkpoint 3.1 (AA).

Under WCAG 2.0 the requirement has been retained but it is a bit of a fudge.
Checkpoint 1.4.5 (which is AA) says:

"Images of Text: If the technologies being used can achieve the visual
presentation, text is used to convey information rather than images of text
except for the following:
Customizable: The image of text can be visually customized to the user's
requirements;
Essential: A particular presentation of text is essential to the information
being conveyed."

We interpret this as meaning that you can use images of text if the required
visual presentation (such as a specific font or an effect such as a dropped
shadow) cannot be achieved using HTML.

This is not permitted at AAA. Checkpoint 1.4.9 states "Images of text are
only used for pure decoration or where a particular presentation of text is
essential to the information being conveyed."


So the answer to your question is that you can meet WCAG 2.0 AA if you use
an image of text as long as the same visual effect cannot be achieved using
HTML and CSS. In my opinion this is unsatisfactory and WCAG 2.0 should have
prohibited this at AA not just at AAA.

Steve Green
Director
Test Partners Ltd


----------------------------------------------------------------------------
----
From: = EMAIL ADDRESS REMOVED = on behalf of Paul Collins
Sent: Wed 11/11/2009 11:12
To: WebAIM Discussion List
Subject: [WebAIM] Image replacement and WCAG2.0


Hi all,

My colleague has asked me if you can use graphical headings in WCAG2.0, so I
guess by that he means using and <IMG> tag with an ALT attribute. I've tried
to find information on this and can't see anything.

I beleive there was nothing specific about this in WCAG1.0, but there was
always the issue that a graphical heading cannot be enlarged (apart from
within a few modern browsers that have ZOOM)

So, I was wondering if anyone can answer the following for me:

- Would it be OK to use a graphical heading and satisfy level AA of WCAG 2.0
- Does anyone know the specific guideline that points to this?

Thanks for any help
Paul Collins

From: Paul Collins
Date: Mon, Nov 16 2009 3:00AM
Subject: Re: Image replacement and WCAG2.0
← Previous message | No next message

Thanks for that Andrew, much appreciated.


-----Original Message-----
From: = EMAIL ADDRESS REMOVED = [mailto: = EMAIL ADDRESS REMOVED = ] On Behalf Of Andrew Kirkpatrick
Sent: Wednesday, November 11, 2009 2:12 PM
To: WebAIM Discussion List
Subject: Re: [WebAIM] Image replacement and WCAG2.0

Related WCAG 2.0 technique: http://www.w3.org/TR/WCAG-TECHS/C30.html


Thanks,
AWK

Andrew Kirkpatrick

Senior Product Manager, Accessibility

Adobe Systems

= EMAIL ADDRESS REMOVED =


-----Original Message-----
From: = EMAIL ADDRESS REMOVED = [mailto: = EMAIL ADDRESS REMOVED = ] On Behalf Of Steve Green
Sent: Wednesday, November 11, 2009 8:43 AM
To: 'WebAIM Discussion List'
Subject: Re: [WebAIM] Image replacement and WCAG2.0

The use of images of text was specifically prohibited under WCAG 1.0 checkpoint 3.1 (AA).

Under WCAG 2.0 the requirement has been retained but it is a bit of a fudge.
Checkpoint 1.4.5 (which is AA) says:

"Images of Text: If the technologies being used can achieve the visual presentation, text is used to convey information rather than images of text except for the following:
Customizable: The image of text can be visually customized to the user's requirements;
Essential: A particular presentation of text is essential to the information being conveyed."

We interpret this as meaning that you can use images of text if the required visual presentation (such as a specific font or an effect such as a dropped
shadow) cannot be achieved using HTML.

This is not permitted at AAA. Checkpoint 1.4.9 states "Images of text are only used for pure decoration or where a particular presentation of text is essential to the information being conveyed."


So the answer to your question is that you can meet WCAG 2.0 AA if you use an image of text as long as the same visual effect cannot be achieved using HTML and CSS. In my opinion this is unsatisfactory and WCAG 2.0 should have prohibited this at AA not just at AAA.

Steve Green
Director
Test Partners Ltd


----------------------------------------------------------------------------
----
From: = EMAIL ADDRESS REMOVED = on behalf of Paul Collins
Sent: Wed 11/11/2009 11:12
To: WebAIM Discussion List
Subject: [WebAIM] Image replacement and WCAG2.0


Hi all,

My colleague has asked me if you can use graphical headings in WCAG2.0, so I guess by that he means using and <IMG> tag with an ALT attribute. I've tried to find information on this and can't see anything.

I beleive there was nothing specific about this in WCAG1.0, but there was always the issue that a graphical heading cannot be enlarged (apart from within a few modern browsers that have ZOOM)

So, I was wondering if anyone can answer the following for me:

- Would it be OK to use a graphical heading and satisfy level AA of WCAG 2.0
- Does anyone know the specific guideline that points to this?

Thanks for any help
Paul Collins