The phrase "text contrast" refers to the difference or distinction between the color or brightness of the text and its background. It determines how easy or difficult it is to read and understand the text. Full definition
I'm betting they figure out how to correct the lighting and text contrast issues as well. (blog.the-ebook-reader.com)
Visual presentation of web pages in high contrast mode is greatly improved to provide additional visual context, while preserving text contrast. (blogs.windows.com)
Appropriated from the front cover of a pulp romance novella, Prince's nurse has a seductive «push - pull» allure to her - her blonde hair and golden text contrasting sharply with the saturated purple background. (christies.com)