What are the best practices for using color contrast and font size on web pages?

1 What is color contrast?

Color contrast is the difference in brightness and hue between the foreground and background colors of a web page. It determines how well the text, images, icons, and other elements stand out from the background. Color contrast is measured by a ratio that compares the relative luminance of the colors. The higher the ratio, the higher the contrast.

3 How to choose and test color contrast?

To choose and test color contrast, you need to consider the purpose, context, and audience of your web content. You should use colors that match your brand identity, convey your message, and create a pleasant and consistent user experience. You should also avoid using color alone to convey information or indicate actions, as some users may not be able to distinguish them. To test color contrast, you can use online tools such as WebAIM's Color Contrast Checker or Chrome's Color Contrast Analyzer extension. These tools allow you to enter or select colors and see their contrast ratio and compliance with WCAG levels.

4 What is font size?

Font size is the measure of how large or small the text appears on a web page. It is usually expressed in pixels (px), points (pt), or relative units such as ems or rems. Font size affects the legibility and readability of your web content, as well as the layout and design of your web pages.

5 Why does font size matter for web accessibility?

Font size matters for web accessibility because it affects how easily people with different visual abilities can read and comprehend your web content. People with low vision, dyslexia, or cognitive impairments may have difficulty reading text that is too small, too large, or inconsistent. Small font size can also cause eye strain and fatigue for anyone who views your web pages. According to WCAG, you should ensure that your text can be resized up to 200% without loss of content or functionality.

6 How to choose and set font size?

To choose and set font size, you need to consider the purpose, context, and audience of your web content. You should use fonts that are clear, simple, and suitable for your topic and tone. You should also use font sizes that are appropriate for the device, screen resolution, and viewport of your users. To set font size, you can use absolute units such as px or pt, or relative units such as ems or rems. Relative units are preferred because they allow your text to scale and adapt to different screen sizes and user preferences. You can also use CSS media queries to adjust font size based on screen width or orientation.