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."

Computer displays where the positions of individual pixels are permanently fixed – such as most modern flat panel displays – can show saw-tooth edges when displaying small, high-contrast graphic elements, such as text. ClearType uses spatial anti-aliasing at the subpixel level to reduce visible artifacts on such displays when text is rendered, making the text appear "smoother" and less jagged. ClearType also uses very heavy font hinting to force the font to fit into the pixel grid. This increases edge contrast and readability of small fonts at the expense of font rendering fidelity and has been criticized by graphic designers for making different fonts look similar.

Like most other types of subpixel rendering, ClearType involves a compromise, sacrificing one aspect of image quality (color or chrominance detail) for another (light and dark or luminance detail). The compromise can improve text appearance when luminance detail is more important than chrominance.

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