What is "cleartype"

ClearType is Microsoft's implementation of subpixel rendering technology in rendering text in a font system. ClearType attempts to improve the appearance of text on certain types of computer display screens by sacrificing color fidelity for additional intensity variation. This trade-off is asserted to work well on LCD flat panel monitors.

ClearType was first announced at the November 1998 COMDEX exhibition. The technology was first introduced in software in January 2000 as an always-on feature of Microsoft Reader, which was released to the public in August 2000.

ClearType was significantly changed with the introduction of DirectWrite in Windows 7.

Word 2013 stopped using ClearType, because "There is a problem with ClearType: it depends critically on the color of the background pixels."