Preview: ClearType – close view, part 1

19 February 2001

Microsoft’s Bill Gates first showed off ClearType at Comdex/Fall in November 1998. At the time there was much speculation as to how the apparent resolution enhancing technology worked. Last month Microsoft’s typography team posted the first publicly available screen shots of the technology in use. We take a close look at those screen shots.


A screen grab from Microsoft Reader. This image features text rendered using Microsoft ClearType and as such should be viewed on a colour LCD display (The ClearType text is tuned to the Pocket PC’s specific LCD display so quality of the type may be lower when viewed on your screen).

Image © 2000 Microsoft Corporation, used with permission.

Big images?
Before we start, I need to explain why the images we are using to illustrate the technology are so large. Additionally you will need some guidance as to how to decode what you see.

All the images shown are at 1,200% the size of the originals. The main reason for this is so that the sub-pixel positioning can be clearly seen. As each sub-pixel is just a third of the size of a pixel on an LCD screen we logically have to show the images at least 300% the size of the originals. That would make our representations of sub-pixels equal to one whole pixel – just enough for you to be able to recognise if you looked at the screen really closely.

We still didn’t believe this made the case clearly, so we increased the size to 1,200%. Frankly this gives huge pixel representations, but that makes it very easy to see detail that would ordinarily be imperceptable.

This necessarily distorts how you perceive the images, this is most obvious when we break down RGB (red, green and blue) values into sub-pixels – details that you could not see in normal usage of an LCD screen. When viewing the large scale images bear in mind that these really represent text at approximately the size of the text on your screen now.

Please also bear in mind, the point of this article is to explain some of the underlying technology, not to reflect its real world usage.