E Ink unveils Kaleido 4 color e-paper, first device is a Hanvon tablet sold only in China

The previous generation, Kaleido 3, appears in e-readers and tablets from Kobo, PocketBook and Boox, while Amazon's Kindle Colorsoft uses a customized version. Kaleido displays place a color filter over an e-paper panel that uses only black and white pigments. That design keeps refresh rates fast, but it produces color images at a lower resolution than black-and-white text and with a limited palette that tends to look desaturated. The added filter also makes plain text appear darker than it does on a screen with only black-and-white E Ink.

E Ink says Kaleido 4 doubles the color gamut volume of its predecessor, increases white reflectance by 15 percent and raises contrast by 50 percent, so plain text should look less muddy. The new display uses an oxide TFT backplane, which the company says lifts refresh rates to as much as 18 frames per second and makes video playback possible. Both reports compare that backplane to a modification Amazon said it made to the Kaleido screens used in the original Kindle Colorsoft.

The two accounts of the new screen's color capabilities differ. The Verge reported that Kaleido 4 is still limited to 4,096 colors and that color images are still shown at a lower resolution than black-and-white text, as with Kaleido 3. Engadget reported that E Ink says the doubled color gamut volume lets the display produce more than 40,000 colors. E Ink's other color technology, Gallery 3, is used in the Remarkable Paper Pro and relies on colored pigments that move to form full-color images, producing richer results, but its slow refresh rate has kept it out of more devices.

Amazon and Kobo have not announced any devices with Kaleido 4 screens. Hanvon's M10C II will pair the display with micro-etched tempered glass intended to cut glare and give a more paper-like feel when writing with its battery-free pen, along with a redesigned front light.