E Ink has demonstrated Spectra, a new type of display that adds a third color to the company's grayscale electronic paper found in e-readers such as the Kindle. The current Spectra screens feature black, white, and red "microcups" that move to the surface of the display as required, though E Ink says other colors will be produced in the future. Engadget reports that the company is also producing displays with blue and green pigmentation.

At present, Spectra is planned for electronic signage such as shelf labels; according to The Digital Reader, which spoke to E Ink at SID Display Week, company representatives would not be drawn on the possibility of the technology making its way into e-readers. Spectra panels will start shipping to retail clients in Q3 of this year.

E Ink has produced color displays before: its Triton technology, which has shipped in products such as the Ectaco Jetbook Color, works by overlaying an RGB array on a traditional black and white E Ink display. However, the company told The Verge last year that Triton hasn't yet gained much traction in the market, and as such is also targeted at signage markets for the time being.