Editing ClearType (section)

==Human vision and cognition ==
ClearType and similar technologies work on the theory that variations in intensity are more noticeable than variations in color.

===Expert opinion===
In a [[MSDN]] article, Microsoft acknowledges that "[te]xt that is rendered with ClearType can also appear significantly different when viewed by individuals with varying levels of color sensitivity. Some individuals can detect slight differences in color better than others."<ref>[http://msdn.microsoft.com/en-us/library/aa970267.aspx Windows Presentation Foundation ClearType Registry Settings]</ref> This opinion is shared by font designer Thomas Phinney (former CEO of [[FontLab]], also formerly with [[Adobe Systems]]<ref>{{Cite web | url=http://www.adobe.com/products/type/font-designers/thomas-phinney.html | title=Thomas W. Phinney II &#124; Adobe Fonts}}</ref>): "There is also considerable variation between individuals in their sensitivity to color fringing. Some people just notice it and are bothered by it a lot more than others."<ref>{{cite web |url=http://www.typophile.com/node/33005#comment-197028 |title=ClearType, in XP and Vista |publisher=Typophile |access-date=2010-01-22 |archive-url=https://web.archive.org/web/20081013085409/http://www.typophile.com/node/33005#comment-197028 |archive-date=2008-10-13 |url-status=dead }}</ref> Software developer Melissa Elliott has written about finding ClearType rendering uncomfortable to read, saying that "instead of seeing black text, I see blue text, and rendered over it but offset by a pixel or two, I see orange text, and someone reached into a bag of purple pixel glitter and just tossed it on...I’m not the only person in the world with this problem, and yet, every time it comes up, people are quick to assure me it works for them as if that’s supposed to make me feel better."<ref name="ClearType Elliott">{{cite web|last1=Elliott|first1=Melissa|title=ClearType|url=http://abad1dea.tumblr.com/post/98281499300/to-not-be-taken-seriously|access-date=15 August 2015}}</ref>

Hinting expert Beat Stamm, who worked on ClearType at Microsoft,<ref>{{cite web|url=http://www.myfonts.com/person/stamm/beat/ |title=Beat Stamm |publisher=MyFonts |date=1999-02-22 |access-date=2010-01-22}}</ref> agrees that ClearType may look blurry at [[Dots per inch#Computer monitor DPI standards|96 dpi]], which was a typical<ref>{{cite web|url=http://dictionary.zdnet.com/definition/Dpi.html |archive-url=https://web.archive.org/web/20081201013347/http://dictionary.zdnet.com/definition/Dpi.html |url-status=dead |archive-date=December 1, 2008 |title=Dpi: Definition and additional resources from ZDNet |publisher=[[ZDNet]] |access-date=2010-01-22}}</ref> resolution for [[LCD]]s in 2008, but adds that higher resolution displays improve on this aspect: "[[Windows Presentation Foundation|WPF]] [Windows Presentation Foundation] uses method C [ClearType with fractional pixel positioning<ref>{{cite web|url=http://rastertragedy.com/RTRCh3.htm#Sec32 |title=Fractional Advance Widths |publisher=The Raster Tragedy at Low-Resolution Revisited |date=2011-03-14 |access-date=2011-03-17}}</ref>], but few display devices have a sufficiently high resolution to make the potential blur a moot point for everybody.&nbsp;.&nbsp;.&nbsp;. Some people are ok with the blur in Method C, some aren’t. Anecdotal evidence suggests that some people are fine with Method C when reading continuous text at 96 dpi (e.g. Times Reader, etc.) but not in UI scenarios. Many people are fine with the colors of ClearType, even at 96 dpi, but a few aren’t… To my eyes and at 96 dpi, Method C doesn’t read as well as Method A. It reads “blurrily” to me. Conversely, at 144 dpi, I don't see a problem with Method C. It looks and reads just fine to me."<ref>{{cite web |url=http://www.typophile.com/node/33005#comment-197660 |title=ClearType, in XP and Vista |publisher=Typophile |access-date=2010-01-22 |archive-url=https://web.archive.org/web/20081013085409/http://www.typophile.com/node/33005#comment-197660 |archive-date=2008-10-13 |url-status=dead }}</ref> One illustration of the potential problem is the following image:

[[Image:FontSmoothingExample.gif|center|Text without rendering (upper portion) and text with ClearType rendering (lower portion)]]

In the above block of text, the same portion of text is shown in the upper half without and in the lower half with ClearType rendering (as opposed to Standard and ClearType in the previous image). This demonstrates the blurring introduced.

===Empirical studies===
A 2001 study, conducted by researchers from [[Clemson University]] and [[The University of Pennsylvania]] on "18 users who spent 60 minutes reading fiction from each of three different displays" found that "When reading from an LCD display, users preferred text rendered with ClearType. ClearType also yielded higher readability judgments and lower ratings of mental fatigue."<ref>{{cite journal | doi = 10.1889/1.1831776 | title=47.4: Empirical Evaluation of User Responses to Reading Text Rendered Using ClearType Technologies | journal=SID Symposium Digest of Technical Papers | date=2001 | volume=32 | issue=1 | pages=1205–1207 | first=Richard A. | last=Tyrrell| s2cid=62772542 }}</ref> A 2002 study on 24 users conducted by the same researchers from Clemson University also found that "Participants were significantly more accurate at identifying words with ClearType than without ClearType."

According to a 2006 study, at the University of Texas at Austin by Dillon et al., ClearType "may not be universally beneficial".  The study notes that maximum benefit may be seen when the information worker is spending large proportions of their time reading text (which is not necessarily the case for the majority of computer users today).  Additionally, over one third of the study participants experienced some disadvantage when using ClearType.  Whether ClearType, or other rendering, should be used is very subjective and it must be the choice of the individual, with the report recommending "to allow users to disable [ClearType] if they find it produces effects other than improved performance".<ref>Dillon, A., Kleinman, L., Choi, G. O., & Bias, R. (2006). [http://www.ischool.utexas.edu/~ct/chi_p618.pdf Visual search and reading tasks using ClearType and regular displays: two experiments] {{Webarchive|url=https://web.archive.org/web/20110120074818/http://www.ischool.utexas.edu/~ct/chi_p618.pdf |date=2011-01-20 }}. CHI ’06: Proceedings of the SIGCHI conference on Human Factors in computing systems, 503-511.</ref>

Another 2007 empirical study, found that "while ClearType rendering does not improve text legibility, reading speed or comfort compared to perceptually-tuned grayscale rendering, subjects prefer text with moderate ClearType rendering to text with grayscale or higher-level ClearType contrast."<ref>{{cite journal | doi = 10.1016/j.displa.2007.09.016 | title=ClearType sub-pixel text rendering: Preference, legibility and reading performance | journal=Displays | date=2008 | volume=29 | issue=2 | pages=138–151 | first=Jim | last=Sheedy}} http://www.pacificu.edu/vpi/publications/documents/ClearTypesub-pixeltextrenderingPreferencelegibilityandreadingperformance.pdf {{Webarchive|url=https://web.archive.org/web/20140809142408/http://www.pacificu.edu/vpi/publications/documents/ClearTypesub-pixeltextrenderingPreferencelegibilityandreadingperformance.pdf |date=2014-08-09 }}</ref>

A 2007 survey, of the literature by Microsoft researcher Kevin Larson presented a different picture: "Peer-reviewed studies have consistently found that using ClearType boosts reading performance compared with other text-rendering systems. In a 2004 study, for instance, Lee Gugerty, a psychology professor at Clemson University, in South Carolina, measured a 17 percent improvement in word recognition accuracy with ClearType. Gugerty’s group also showed, in a sentence comprehension study, that ClearType boosted reading speed by 5 percent and comprehension by 2 percent. Similarly, in a study published in 2007, psychologist Andrew Dillon at the University of Texas at Austin found that when subjects were asked to scan a spreadsheet and pick out certain information, they did those tasks 7 percent faster with ClearType."<ref>Kevin Larson (May 2007) "[https://spectrum.ieee.org/the-technology-of-text The Technology of Text]", ''[[IEEE Spectrum]]''</ref>