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When typing in text you want to consider the color contrast between the text and the background. For small text (under size 18), a good contrast ratio to aim for is 4.5:1 or higher. For bigger text (over size 18) a good contrast ratio is 3:1 or higher. Black text on a white background or 21:1 is considered to be the most accessible contrast ratio. To check if your color contrast ratio is sufficient, you should use Adobe’s Color Contrast Analyzer tool.
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This chart has a very low color contrast ratio.  |
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This chart has a very high color contrast ratio.  |
As you can see in the example, good color contrast makes the text easier to read for the viewer.
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When trying to show information in a table, never use color as its only indicator. Some users may not be able to see color. Others may not be able to tell colors apart. The best way to show information is to have multiple indicators. One of them can be color, but the other should be text, either normal text or alt text.
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This table only uses color to convey meaning. This table would be considered inaccessible because some readers may not be able to distinguish the colors and their meaning.  |
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This table uses color and text to convey meaning. It is accessible now because there is a second indicator to what the information is telling a reader.  |
Creating a Text Description
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Move the location of your chart or graph to a new location next to cell A1.
Click cell A1 and type in a brief description of the details in your chart. Then click the Wrap Text button to contain the description to cell A1. This will allow screen readers to explain the details of the charts to the readers and will make it easier for students with disabilities to understand the data.
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While this image does contain a description, it does not explain everything in the graph. It fails to mention the data within the table. Anything in the table or graph or chart must be covered in the long description.  |
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This long description tells the readers everything they have to know about the graph.  |
Adding Visual Queues
When using color to convey information, always be sure to add an extra visual queue. For many readers, color is hard to see, so they need another way to read the data.
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This chart does not have any additional queues to help the reader. Color blind users may not be able to tell the difference between the colors. If that is the case, it would be very hard for them to understand the data.  |
To add an additional queues, click the chart. Click the Plus shaped button and add Data Labels. The Data Labels will appear, but they may not be the ones you want. The names could appear on the chart, but so could the numbers of sales, or a combination of both. In this example we want the names to appear over the data lines. To make this change,
Click on the chart, and click the Plus Icon for Chart Elements.
In the expanded menu, click on the arrow next to Data Labels and click More Options.
In the Format Data Labels Section, go to label options and click Series Name.
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This chart includes the names of the employees above their data. This will help readers know what data belongs to which person without relying on color.  |
Section 2.3: Using Cell Styles
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