"Sepia mode" refers to a setting or effect that makes photographs or images appear vintage or old-fashioned by giving them a warm, brownish tint. Full definition
And we do try to be aware of how that color is going to render when someone is viewing the book in sepia mode, or in night mode, or any of those things, just to make sure that nothing breaks. (epubsecrets.com)
I decided to drop a perfectly personalized interface of Kindle app: Caecilia font, medium size, with sepia mode. (ebookfriendly.com)
The text color in sepia mode could benefit from being a smidge darker, and that's similarly nonadjustable. (macworld.com)