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Tag: color

A11y 101: 1.4.11 Non-text Contrast

A11y 101: 1.4.11 Non-text Contrast

Published on April 28, 2025

We previously discussed contrast under Guideline 1.4.3 Contrast. So why is there a second AA criteria for contrast? The earlier guideline covers only text. With the introduction WCAG 2.1, we need to start being aware of the contrast of graphical items, particularly active controls. But the way we test contrast for graphics is different than how we test contrast for text, kind of…

Just as we did in testing text contrast, we’ll need a contrast checker. There are many out there, but for this article I’ll be using Level Access’s Accessible Color Picker. The one you use may be different, but the concepts should be the same.

What does WCAG say?

The visual presentation of the following have a contrast ratio of at least 3:1 against adjacent color(s):

User Interface Components: Visual information required to identify user interface components and states, except for inactive components or where the appearance of the component is determined by the user agent and not modified by the author;

Graphical Objects: Parts of graphics required to understand the content, except when a particular presentation of graphics is essential to the information being conveyed.

Technical words for technical people. Welcome to the world of writing standards!

“The visual presentation…contrast ratio of … 3:1 against adjacent colors.” Cool. We’re familiar with 3:1, we know how to use the contrast checker, let’s test!

If it were that simple

There is a key phrase here that complicates the testing, “adjacent colors.” Our control must have a 3:1 contrast ratio against adjacent colors. Colors. How often have you tried to make a color palette with three colors that all have a 3:1 ratio? If you haven’t yet, it can be quite difficult. The more colors you add to the palette, the harder it gets.

But this adjacent colors is not expecting you to have a 3:1 contrast between all colors. The second bullet contains important information too. “Parts of graphics required to understand the content…” Of course there is more to it, but let’s start here. We’ll start with a simple button for a disclosure. Let’s get our example from WCAG.

This button has blue text on a gray button. The button has a darker gray border and sits on a white background. Most people will test the background color of the button to the white. And that is one way to do it. In this case, it will result in a false positive. First, because there is a border, the gray background is not adjacent to the white. So we measured the wrong thing. We need to compare the border with both the white background and the gray button background. This is because the border defines the edge of the control. This success criterion is about discerning actionable controls.

When we do this test, we find out that neither passes.

Border of #EEEEEE against a background of #E1E1E1 showing a contrast ration of 1.127:1

The border is #E1E1E1 and the gray only has a 1.127:1 contrast.

Border of #E1E1E1 against a background of #FFFFFF showing a contrast ration of 1.308:1

When the border is against white, it only bumps up to 1.308:1. But we’re not done testing this unit. We’ve checked the border against adjacent colors and it fails. But WCAG gave us an out that the W3C is using on their own site. “Parts of graphics required to understand the content…”. What is important to understand the content? Is it the background, the border, or is it something else, say the text of the button.

The text on its own has enough contrast against the gray. No additional graphic is needed to understand the control.

Text color of #1F6DA6 and background of #EEEEEE showing a contrast ratio of 4.768:1

As seen in this image, the blue text against the gray has enough contrast to meet the 1.4.3 Text Contrast rules, and it still supports 1.4.11 despite the background failing.

Summation

When testing 1.4.11 non-text contrast:

You need a contrast checker
Check the graphic for any borders
If there are borders, use the border for the foreground
Check colors on both sides of the borders
If that fails, check the content of the control
If one of the three pass, the control passes this guideline

Thoughts, questions, have a different method? Reach me on LinkedIn and BlueSky to discuss the topic!

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A11y 101: 1.4.3 Contrast (Minimum)

A11y 101: 1.4.3 Contrast (Minimum)

Published on March 25, 2025

One of the most common issues I see when testing is the content not having enough contrast. With 1.4.3, we’re focus on the contrast of text. This can be text in an image or just on the page. Later we’ll talk about the contrast of active controls in 1.4.11.

Designers commonly complain that they can’t design with the restrictions that WCAG has in place for contrast. At the same time the great designers love restrictions. So your reception will vary when you work with a designer. Remember, they don’t get a choice about adhering to the contrast levels set out.

Defining Contrast

Outlined in WCAG, we have two contrast levels we need to look out for text. We divide text into “normal” or “body” text and “large” text. Body text is all text smaller than 18 point and not bold. If it is bold, it can be as small as 14 point. Everything bigger than that is large text.

This is body text at 14 point.

This is large text, bold at 14 point.

This is large text at 18 point.

1 point does not equal 1 pixel.
1 point is actually 1.3 CSS pixels.

If you are like me, you are looking at those blocks thinking that they don’t look like 14 and 18 pixels. Heck, this body text looks the same size as the 18 point. Well that is because I use a larger than normal font for easier reading. Additionally, 1 point does not equal 1 pixel. 1 point is actually 1.3 CSS pixels. This means 14 point is really 19 rendered pixels. Eighteen point comes out to 24 pixels.

How do we determine what size it is?

In Chrome and Firefox, the web inspector tools offer a “Computed” section. After highlighting the element in the code, switch to the computed tab and look for font-size. This will show the rendered pixel height regardless of what measurement you used to set the size. In addition to points, font sizes can be set with EM, REM, pixel, percentage, viewport height and width, just to name the most common.

Chrome's developer tools opened to the Computed tab. It shows a list of CSS properties and their values, including font-size set to 14.4px.

What are the contrast levels?

Now that we know how to measure our fonts, let’s look at the contrast levels. We have two remember. One for body text and one for large text. For body text, the contrast ratio is 4.5:1. For large text the contrast ratio is 3:1. There are many contrast checkers on the market, so feel free to find one and use it.

My personal favorite is Level Access’s Accessible Color Picker for Chrome. Full disclosure, I currently work for Level Access. However, I’m not pitching the company. This color contrast tester not only provides the contrast and if it passes A, AA, or AAA, but is also helps guide you to fixing the colors.

On the side of the contrast values is a five by five grid. Your picked colors are in the middle. If you move up or down in the grid, options are shown for your background. Moving left or right in the grid changes the foreground. These options may have better contrast.

As a developer using this tool, I look for contrast pairs that don’t work. When I find an issue, I will suggest a color combo from these suggestions that does work. Then the designer just needs to approve, moving the process forward.

What is APCA?

The WCAG is imperfect. It is a volunteer organization of hundreds trying their best to develop accessible rules the majority can agree on. On of the flaws is in the algorithm for finding contrast. There are combos that fall below WCAG standards that are no issue for people with color blindness. There are also combos that meet the criteria, but are unusable because they irritate eyes.

When the efforts to bring WCAG to the next level beyond 2.2, those involved began investigating other contrast algorithms. APCA is one of those. It looks like it will be how we evaluate contrast in the future. However, if you are building a website today it doesn’t matter. The current rules and laws all point back to WCAG 2.x and the algorithm used in that is not APCA. To comply with the current law, you must test colors under the current algorithm. This is true even if you use APCA to choose your colors. If you can use combos that pass both, you are future protecting yourself.

Have questions on this topic? Find me on LinkedIn and BlueSky to chat!

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A11y 101: 1.4.1 Use of Color

A11y 101: 1.4.1 Use of Color

Published on March 10, 2025

Color is important. Color allows us to discern whether our fruit is ripe. We use color to control traffic. We spend time in school teaching kids their colors. We ask them to “Identify the red one.” But not all of us see color the same way, and some can’t see it at all. We cannot rely on it to be the sole means of communication.

A little color theory

Light hits an object, and the object applies a filter. This filter absorbs or reflects bands of the light spectrum. The filter is influenced by the materials used to make the object. This could be a pigment, but blue pigment is very rare in nature. When you see blue in animals, it is usually due to the structure not blocking blue light.

The eyes are made up of cones that absorb light. Humans have 3 cones, red, blue, and green. How much light hits each cone type also helps determine the color. Imagine a brand new tennis ball in full light glowing neon yellow. What happens if we cut the light in half? Is it still neon yellow? What if there is just enough light to see the ball? What color is it then?

Or was the tennis ball really neon green? Color blindness is the result of damage to the cones or them not fully developing. There are brain and optical nerve injuries that can cause it as well. To put it short:

My navy blue is not the same as your navy blue.

Trying not to put the horse before Decartes, but our brains are amazing machines. It takes in a extreme volume of stimuli and builds the world around us. While we teach each other a standard that allows us to participate in a society. But when you view blue (or any color), you don’t just get blue light, you get color influence. The colors surrounding your object will change how the colors appear.

These two circles are the same color. But they don’t look like it due to the backgrounds.

Two grey circles of the same color against different backgrounds. One background is pink and the other is purple.

My wife has suffered several strokes and TBIs. We don’t see the same colors. It’s especially noticeable in the transition zones between colors. She asked me to grab something for her, but I couldn’t find it. She told me it was orange. Looking around I thought I found it, but it was red. She swears up and down it is orange. We’ve repeated this discussion with pinks, blues, and greens as well.

We each interpret colors differently. Therefore, it is vitally important that color is not the only way of communicating important information.

Like this article? Then please share. If you want to discuss it, find me on LinkedIn or BlueSky. If you liked my philosophical joke, leave a note and use the “polyphony.”

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A11y 101: 1.3.3 Sensory Characteristics

A11y 101: 1.3.3 Sensory Characteristics

Published on February 17, 2025

I have a bad habit of saying, “this is easy” or simple. It’ll only take a moment. Like I said, a bad habit that I try hard to break. Why? Just because it is easy to me doesn’t mean it is to you. I was about to start this off with, “This is pretty much straight forward and don’t reference anything requiring senses.”

And I realize, that this isn’t that simple. I’ve been doing this for over two decades as of this writing. Today may be your first day. English may not be your first language. Maybe you can’t relate to the idea of senses.

What do we mean by Sensory Characteristics?

All animals on the planet have the ability to experience their environment. They do this with their senses. Senses are built in detectors to assess our environment. In the accessibility industry, we create solutions. These solutions are for people who may have malfunctioning senses.

When we are little, we are taught about our 5 major senses: Sight, Taste, Touch, Hearing, and Scent. But we also have senses that can detect electrical stimuli, heat, cold, our awareness in space. If you tell someone to find the green button, you’ve violated the success criteria.

So how do we avoid it?

First, we make sure that everything has a proper accessible name. Next, we make sure it unique to the page we are on. It’s super easy to say, “click the submit button” in your instructions if there is only one submit button.

Of course we want to keep the page as simple as possible, so we probably won’t use instructions like that. We wouldn’t say, “click the triangle.” Instead, we should let the construction of the page tell us what to do next.

This looks like first coding the HTML so that if nothing else loads everything is presented and understandable. You can’t position items in a visual order or paint them pretty colors. You also can’t make them do magic. Therefore, we need to rely on the content itself. If your content can’t stand on it’s own, rewrite it.

With the content corrected, we can build out the site. Paint it, position it, then test it. Does it still make senses in the reading order? Focus order?

Lastly, teach the team. Make it an internal standard. Put in monitoring just in case someone makes a mistake.

Want to discuss this more? Come say hi on BlueSky and LinkedIn.

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