Re: contrast for images of text

Adam wrote:

> So then images of text would fail in A which I believe
 > to be reasonable.

I assume that you refer to "images of text with poor contrast". I agree 
that they would fail 1.4.1 since, for low vision users, the embedded 
text is conveying the information relying on color alone. Even if the 
text is provided in an alt text, for example, many low vision users 
don't rely on screen readers and therefore might miss the information 
completely.

Indeed, I see the technique regarding the "distinguisable links" as a 
logical interpretation of SC 1.4.1 that implicitly recognises the 
importance of contrast. Being a "sufficient technique" for SC 1.4.1, it 
seems to suggest that the contrary would be a failure, although no 
failure exists to indicate that. Moreover, the technique does not really 
refer to color, but contrast ratio between links and the surrounding 
text, which makes me think that it should apply to 1.4.3 and not 1.4.1. 
In fact, the role information is there, so color is obviously not the 
only way to convey the presence of the link. That said, I think that the 
technique is properly attached to 1.4.1, because it correctly assumes 
that not providing contrast is equivalent to relying on colour.

I can even imagine a weird situation where the level A is theoretically 
met, although in practice there is a severe barrier for many users.

Imagine the following image of text that acts as a heading for a link 
"more info":

- Text: "Special offer! WiFi router for only $5.99"

- Color: light gray (#CCCCCC) over white

- Fails 1.4.3 AA (contrast ratio = 1.6:1) and 1.4.5 AA (image of text), 
maybe fails 1.4.4 also, although it does not refer to "images of text". 
In any case, it is also AA.

- "Pass" 1.3.1, 1.4.1 and 4.1.2 due to the programmatically determinable 
text included in the @alt, apparently no more "A" criteria involved)

Below this image of text we have a link "more info" in normal text, with 
a gray Color (#717171) over the overall white background.

- Pass 1.4.1 (the information of the link itself "more info" does not 
rely on color, but anyway the contrast ratio with the "surrounding" text 
is 3.0:1)

- Pass 2.4.4 (level A), since the "context" is provided with the image 
of text (@alt for blind users and the image itself for sighted users, 
since it passes "A")

Thus, we have an image of text that is virtually invisible for anyone 
that has not a more-than-perfect vision (but passes A), and a link that 
is perfectly visible and passes level-A because the context is there.

The described situation is more or less common, maybe the low contrast 
is not as critical, but I've seen many "iamge headings" with contrast 
ratios of 2.0:1 or similar, which are almost invisible for me.

Therefore, I think that a technique similar to the "distinguisable 
links" should be created for images of text that have not enough 
contrast, and even a pair of failures of SC 1.4.1 due to "relying on 
color with an insufficient contrast ratio to convey information", or 
something like that.

Kind regards,
Ramón.

Received on Wednesday, 30 April 2014 09:04:11 UTC