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Re: alt text size

for

From: Jukka K. Korpela
Date: Aug 21, 2006 12:50AM

On Sun, 20 Aug 2006, zara wrote:

> I am looking for documentation on maximum size of text equivalents.

I first thought that you are referring to the font size of alt texts,
which tends to be rather small, defeating much of their usefulness to
sighted users. But apparently you refer to the _length_ of alt texts.

Roughly speaking, the alt text length should vary from zero to about
twenty characters in typical cases. Anything longer is quite often a
misguided and misguiding attempt at describing what there is in a picture,
rather than proving a text _equivalent_ to it. If an image would need a
longer alt text, then the alt attribute is probably not a sufficient
method for conveying the message of the image.

No strict limits should be imposed, but as a rough rule of thumb,
the text should usually be 0 - 20 characters, but it can be up to 50
characters in some cases, but anything longer than that will create
considerable problems. For a longer explanation, including notes on the
"magic" limit of 50 characters, see
http://www.cs.tut.fi/~jkorpela/html/alt.html#length
(Of course, if you _only_ think about people who use nonvisual browsers,
things are different. But I don't think such a limited scope is suitable.)

> We are writing a proposal for a Web accessibility standard for the
> government of Qu