Textual content should have high contrast ratios against their backgrounds in order to be legible to readers. Contrast ratios can be checked using WebAIM’s Contrast Checker. Please note that there are two ways to resolve Low Contrast PDF issues. If you have exported your PDF from another file format, it’s best to resolve the issue in the original format before exporting it. You can also resolve the issue directly in the PDF using Adobe Acrobat Pro.