The Importance of Font and Color in Readability
Two email newsletters had important information, but I struggled to read them. The reason: Font and color abuse. They were reminiscent of the websites of the early 1990s when designers experimented with loads of colors and fonts.
Too many colors and font styles distract from the content and make it harder for people to read. As much as I love the color red, it won't do well as the major font color on a website. Red works fine as headers and other uncommon text usage.
I don't proclaim to be an expert in colors or design. But my eyes work well and they know what they don't like because it hurts or makes reading a challenge.
Besides, too many colors and font styles reek of unprofessionalism. It's something you expect children to do. Mine go crazy with their computer presentations using every major color, lots of transition effects, and half of the fonts on their computers. They're learning and exploring. Of course, a company or an organization should keep learning and putting creativity to work, but not at the expense of their readers' eyes.
Also, consider that more people read content on mobile devices, which don't always convert content the way you expect.
Newsletters don't have standards, but publishers learn by reading, listening to feedback, and looking at other examples. These rules provide a general rule of thumb to help you, but exceptions always exist.