E Ink Unveils Kaleido 4 Color E-Paper With Sharper Contrast, Faster Refresh

E Ink has announced Kaleido 4, the next version of its color e-paper screen technology. The company says the new panels improve color saturation, contrast, and refresh speed compared with Kaleido 3, which is used in e-readers and tablets from brands including Kobo, PocketBook, and Boox. Amazon's Kindle Colorsoft uses a customized version of that earlier technology.

The Kaleido approach differs from E Ink's Gallery displays, such as the Gallery 3 panel in the Remarkable Paper Pro. Gallery screens move colored pigments to form images, while Kaleido places a color filter over a black-and-white e-paper panel. That design allows faster refreshes but produces color at lower resolution and with a limited palette that can appear washed out. In a further trade-off, the color filter can make ordinary text look darker than it does on a purely black-and-white E Ink screen.

E Ink says Kaleido 4 doubles the "color gamut volume" of its predecessor, which should make color images look better. Even so, the technology remains limited to 4,096 colors, far fewer than the millions produced by modern LCD and OLED displays. Color content is still shown at a lower resolution than black-and-white text. The company also claims white reflectance rises by 15 percent and contrast improves by 50 percent, meaning plain text may look less muddy than it often does with Kaleido 3.

Gallery 3 offers what may seem like superior color quality, but it has not appeared in many devices because its slow refresh rate can feel frustrating. Kaleido 3 refreshes much faster, and Kaleido 4 adds an oxide TFT backplane, similar to what the Kindle Colorsoft is said to use. E Ink says this pushes performance further, with refresh rates up to 18 frames per second, enough to play back video.

No new devices from Amazon or Kobo have been announced with Kaleido 4 screens. The first product to adopt the technology will be the Hanvon M10C II, a note-taking tablet that will be sold only in China. It will pair the Kaleido 4 display with a micro-etched tempered-glass surface intended to cut glare and give a more paper-like writing feel when used with a battery-free pen.

The announcement points to the slow, incremental nature of color e-paper. The core compromises of the Kaleido line, lower color resolution, a restricted palette, and darker text, have not disappeared, but E Ink is addressing some of the most common complaints. The faster refresh and higher contrast could make these screens more usable for note-taking and perhaps simple video. The absence of Western device partners at launch means the impact will initially be limited to the Chinese market. How much Kaleido 4 improves the reading and writing experience in practice will depend on the first devices, which have not yet been independently tested.