
One of our authors received an email from the Amazon Kindle support team informing her that they had received a complaint from someone trying to read the author's book using the black background for reading (very useful at night, just ask my wife). Here is the message:
“Text in your book is unreadable for readers using color devices and reading on a black background. This may have occurred due to forcing the font color to black in your source file. To correct this issue, please remove all forced formatting from your font.”
After doing some research and experiencing the problem myself (the image at the top of this post is from an eBook marketing book I've been reading*), I came up with three pointers.
If You Use Word to Draft Your Manuscript
MS Word style sheets allow you to define the font color of your text. As much as you might enjoy reading a color other than black, resist the temptation to change it to anything other than Automatic.

Why? Unlike a print book, certain text characteristics are up to the reader of the eBook. Font size, line spacing, background color, even the font itself are settings often controlled by your reader.
A setting of Automatic let's the reader, and their eReading software, control these aspects of the presentation. If you define the text as sepia, and the reader likes to read with a sepia background, they won't see any words on the screen.
Fixing the CSS File
In our case the problem was due to settings used when the original paper book was scanned by the author's scanning service. It set the font color to black and I had to remove two color tags from the CSS file:
color: black;
color: windowtext;
I also had to look for and remove any tags for background color.
Using Shading

A similar problem occurs when you use shading, for example, to highlight row headings in a table. My advice is to go for contrast and limit the number of combinations, again leaving the font color as Automatic.
Here are two examples of the same table, each formatted differently. The first uses two different shades of grey. The second example uses one grey box and a “plain” box.

When you view this example with a white background the top row is boring: white with black (Automatic) letters. But when your reader chooses a black background the text is perfectly readable!
Bottom line: your reader now has control over your book's presentation. Don't try to circumvent that or your book might get a quality control notice from eBook store management.
* I intentionally smudged identifying information in the image of this eBook page.
Actually one of my customer’s had the same type of issue. She got the following message
“Text in your book is unreadable for readers using black color schemes – preparation method. You can see this issue at the following location(s): 79”
So I started to search and I found your blog post. This is very helpful. Thank you.
Nitin
Amazon seems to be cracking down on this. Thanks for stopping by.
Hi All,
I just purchased the Kindle (digital) version of Ann Marget’s book and the text in it not legible. Sentences and words are run on. My laptop is in sync with my Amazon account eKindle books. Please help. Many thanks!
You need to visit the book’s page on Amazon where you bought it. There should be a heading, maybe down the page, that says “Report an issue” and look for the heading “Does this item contain quality or formatting issues?”