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There is more than one kind of eye fatigue

Asthenopia is the formal term for describing what is usually called eye fatigue. While eye fatigue has been around long before computers, spending many hours in front of computer monitors certainly causes eye fatigue for a lot of people. I’m keenly interested in understanding eye fatigue and what can be done to prevent it.

Surprisingly when you go to an eye doctor today, there are no direct tests of eye fatigue in the same way that there are tests for high blood pressure. Instead you’re asked to respond to questions like: Do you have blurred vision? Do you feel ache or pain around the eyes? Do your eyes feel tired at the end of the day? If you answer yes frequently enough, then you have eye fatigue.

The pain associated with eye fatigue can be felt in a variety of different ways. Some people feel eye fatigue as ache, strain, and/or headache, typically coming from the back of the head. Other people feel it as burning, irritation, and/or dryness in front of the eye. Others experience vision problems like double vision and blur. These would all be called eye fatigue.

There are many situations that are known to cause eye fatigue, and reducing these factors is a good strategy for reducing eye fatigue. Some factors are related to common office arrangements such as the computer monitor requiring an upward gaze because it is above eye level, a glare sources directed at the user’s eyes, or a flickering light in the environment. Text read from too short a distance which forces your eyes to turn in towards each other (e.g. 15cm) or text that is too small for a user will both cause eye fatigue. Eye fatigue can also result from vision problems such as uncorrected astigmatisms or the inability to adequately change lens power enough to focus on the reading material.

Sheedy, Hayes, & Engle investigated if different factors known to cause eye fatigue were more likely to result in particular kinds of symptoms. To test this they had study participants read text while they intentionally induced eye fatigue. Participants would read text in a variety of unpleasant situations including having a bright light pointed at their face, with a strobe light in the room, with too small text, with text placed close to their face, and while wearing glasses that simulated astigmatism. After each condition the participants answered questions about which eye fatigue symptoms they experienced.

They found that reading with difficult environmental conditions such as upward gaze, glare, flickering light, or small text caused the participants to report symptoms of burning, irritation, and dryness. While reading with internal problems like having to turn your eyes inward, astigmatism, and stress on the focusing lens caused the participants to report ache, strain, and headache.

There is more than one kind of eye fatigue. Understanding the physiological mechanisms that cause eye fatigue can help us reduce its effects.

Cheers, Kevin

Sheedy, J.E., Hayes, J., & Engle, J. (2003). Is all Asthenopia the Same? Optometry and Vision Science, 80 (11), 732-739.

ClearType improves the efficiency of typical office tasks

In two earlier posts I talked about studies that showed that word recognition is 17% more accurate and sentence comprehension is 5% faster with ClearType. Given these findings we should certainly expect that that there are reading benefits for ClearType when reading extended text. But what about other common office tasks that involve reading, but are more complicated than just straight-forward reading? Andrew Dillon and his colleagues at the University of Texas’ School of Information investigated both of these questions.

Participants in the extended duration reading study read five screens full of 12 point Arial text rendered with ClearType and five screens with 12 point Arial black & white rendered text. All of the expected controls were used so, for instance, half the participants saw a particular article rendered with ClearType, and the other half saw the same article rendered in black & white.

As expected from the earlier findings, people were reliably faster with ClearType without any differences in accuracy of visual fatigue. Participants read for 9 minutes and 9 seconds on average with ClearType, and 9 minutes and 39 seconds with black & white rendering, a reading speed advantage of about 5%. The reading speed for each of the five screens of text was also faster with ClearType.

More interesting was the participants’ performance on a spreadsheet scanning task. In the spreadsheet scanning task participants were asked to perform a task that involved more navigation around the spreadsheet than would typically occur while reading a regular page of text. In the below example, participants were asked how many books are acceptable for an age 4-7 reading level and cost $21. To answer this question, participants need to look at each row of text and count how many rows meet both conditions.

Dillon and colleagues found that people performed the tasks reliably faster when the spreadsheet was rendered in ClearType without any differences in accuracy or visual fatigue. Participants took on average 4 minutes and 40 seconds to complete tasks with ClearType compared to 5 minutes and 4 seconds with black & white rendering, a difference of about 8%.

ClearType not only improves reading speed for traditional page reading, but also improves the efficiency for completing any task that involves recognizing words or numbers.

Kevin Larson

Dillon, A., Kleinman, L., Choi, G. O., & Bias, R. (2006). Visual search and reading tasks using ClearType and regular displays: two experiments. CHI ’06: Proceedings of the SIGCHI conference on Human Factors in computing systems, 503-511.

Uhhhh... I’m, like, angry at numbers.

A teacher asks Butt-head if he is angry for some reason

Butt-head: Uhhhh... I’m, like, angry at numbers.

Beavis: Yeah, there’s like, too many of them and stuff.

If Beavis and Butthead were typographers, they would be ecstatic. For typographers, the more numbers styles, the better, and with the advent of OpenType a whole new world of rich typography has opened up, to allow for this. As well as allowing for typographic features, such as small caps, and ligatures to be included in one font file, OpenType also allows for the addition of many different styles of numbers. These different styles can then be defined in markup language such as XAML. To find out in much more detail about support for OpenType typography features in XAML, see this MSDN article.

In this post I would like to to talk about the uses of Old Style Numbers. As with letters of the alphabet, numbers also have uppercase and lowercase forms. Typographers have many names for them, OldStyle Numbers, Text Figures, or they are sometimes called hanging figures. They are not new, and were commonly used in centuries past, and are still often used today. You may have seen some fonts that have this different number style. If you have ever seen the font Georgia on a web page, you most certainly have, and you most likely have seen them in books or magazines you have read. You may not have noticed them but they do look different, and they are designed to be used when the surrounding text is set in lowercase letters or small caps. The overall effect of this is that the numbers blend in well with the lowercase letters, giving a much more even flow to the text. All of the new fonts in the ClearType Collection include this style of numbers, as well as other styles such as Lining Numbers, and Small Caps numbers which can be accessed through OpenType. The new fonts are intentionally targeted at longer term reading, such as web pages, electronic magazines, business documents, longer emails, etc, where the numbers are most likely to be surrounded by lowercase letters.

Below is an example of the OldStyle figures from the font Calibri Regular

 

For more reading on number styles see this article on Creative Pro by John D. Berry. For much more on OpenType see this longer article published on the Microsoft Typography website, written by John Hudson. As more designers discover the possibilities of using OpenType, we are likely so see more of these styles of numbers being used in setting text, and this is a good thing for readers.

Beavis, Butthead,  if you are still reading, sorry about that!

Mike

A blast from type past!

When Windows 2000 launched, there was a new typeface included called Palatino Linotype. What was special about it? Quite a bit actually. The description that comes with the typeface explains why.

“Palatino Linotype is the definitive new version of Hermann Zapf’s Palatino, which since its design in 1950 has become one of the world’s most widely used typefaces. For this new digital version, Professor Zapf has drawn numerous additional characters to include an extensive range of ligatures, numerals, fractions and support for Cyrillic and both monotonic and polytonic Greek. Special care has been taken to enhance the quality of the letterforms when displayed on the computer screen, ensuring that Palatino Linotype is highly legible whether displayed on the screen or in print. This typeface is ideal for use in extended text settings such as books, periodicals and catalogs.”

Palatino Linotype was the first western OpenType font Microsoft shipped. It has built in support for more sophisticated typography, including the ability to set ligatures, true small caps, different numeral styles, and a variety of special alternate characters, such as the swash Capital Qu combination, as seen in the sample above. I will be following up in future posts on the typographic power of OpenType which is now fully supported in Windows Presentation Foundation. For an online demo of the font in action, please visit Tim Sneath’s site here, where you can also view some of the markup in XAML, showing how the OpenType features can be specified.

Mike

Update: To view the online demo, you will need to be running Windows Vista, or to view on XP, the .NET Framework 3.0 should be installed.

The Technology of Text

Kevin Larson on our team recently had an article published in Spectrum IEEE. Here is a link to the online Version.

Edit: Update link reference

The ClearType Font Collection

Now that Vista and Office 2007 have shipped, we would like to send out a pointer to some online typographic samples of the ClearType font collection. All of these brand new fonts ship with Vista, and Office 2007. Calibri and Cambria are included in Office as the new defaults.

You can find the samples here.

Sample layouts for each font are provided as .XPS  (XML Paper Specification) files. For viewing options visit this page.

Mike

Missed Opportunity for Ligatures

In 1916 Legros & Grant published their classic printers handbook Typographical Printing-Surfaces. In a small section in the middle of the book they advocate spelling reform for a different reason than most.

There have been many calls for spelling reform for the English language. The problem is that there are roughly 45 sounds in the language, but only 26 letters. The usual complaint is that causes spelling to be more difficult than necessary: traveler or traveller? embarass or embarrass? gauge or guage? untill or until? weird or wierd?

It is called a regular orthography when there is a 1:1 relationship between the sounds in a language and the letters to represent those sounds. Having more sounds in a language than letters to represent those sounds is called an irregular orthography. All alphabetic writing systems fall somewhere on this continuum. English is known for having an irregular orthography while Spanish is known for having a very regular orthography. Some researchers have proposed that dyslexia is more prevalent in countries that have irregular orthographies than countries that have regular orthographies. Reducing dyslexia seems an even better reason to call for spelling reform.

Legros & Grant provided a third reason. They pointed out that using two letters to represent a single sound is inefficient both for the amount of paper used and in the amount of time for compositors to create a page. Compositors are the people who manually creates pages of text to be printed by arranging all the metal slugs of lead that each carried a letter. L&G proposed creating two new ligatures: th and ng. They calculated that by creating these ligatures, which are associated with unique sounds in English, that they could save 3-4% in compositors time and in the amount of printing. They calculated the annual savings at 350,000£ (inflation adjusted that is over 6 million pounds).

Legros & Grant’s proposal for spelling reform is particularly elegant because it provides an easy transition path with relatively little re-learning. The ligatures are not completely new letters, but modifications of existing letters. Both th and the th ligature could comfortably exist during a transition period. Unfortunately we’ve missed the chance to save compositors’ time.

Cheers, Kevin Larson

More on Linespacing

Typography Tip #3 recommends setting linespacing in Word to a multiple of 1.2. This has the effect of making each line of 10 point text 12 points tall. Is this a good recommendation?

Yes.

Miles Tinker ran a huge research program investigating typographic variables from the 1920s to the 1950s. Linespacing is one of many variables he thoroughly investigated. He collected data with multiple sizes of text and multiple line lengths. His standard methodology measured people’s reading speed while simultaneously carrying out a comprehension task that ensured that the text was fully understood. This ensured that he was only measuring reading speed differences and not comprehension differences.

When examining reading speed with 10 point text, Tinker found little difference between reading speed with text set solid and adding 1 point of linespacing (multiple of 1.1). A statistically reliable speed advantage was found by adding 2 points of linespacing (multiple of 1.2). And adding more linespacing past 2 points did not further improve reading speed. 2 points of linespacing appears to be the critical amount of extra space needed to separate lines, as 2 points was also optimal for both 8 and 12 point text sizes.

Linespacing with 10 point text:

Amount of Additional Linespacing	Reading Speed Difference in Percent
Set Solid (control)	0.0
1 point	-1.0
2 point	+5.2
4 point	+2.8

 

Bonus: In the comments for Typography Tip #3, Adam Twardoch asserts that the line length effects the amount of needed linespacing. Tinker’s data does not back up this assertion. This table shows that 2 points of linespacing performed the best at each line width tested.

Linespacing with 10 point text. Reading speed difference in percent compared to 19 pica line (3.2 inch) with 2 points of additional linespacing:

Line Width	Set Solid	1 point linespacing	2 point linespacing	4 point linespacing
9 pica (1.5 inch)	-9.3	-6.0	-5.3	-7.1
14 pica (2.3 inch)	-4.5	-0.6	-0.3	-1.7
19 pica (3.2 inch)	-5.0	-5.1	0.0 (control)	-2.0
31 pica (5.2 inch)	-3.7	-3.8	-2.4	-3.6
43 pica (7.2 inch)	-9.1	-9.0	-5.9	-8.8

Cheers, Kevin Larson

Miles A. Tinker, Legibility of Print, Iowa State University Press, 1963.

Word jumble hoax debunked

I’ve previously talked about the Aoccdrnig to rscheearch at Cmabrigde uinervtisy hoax. The study described in that hoax has recently been carried out by a team at the University of Massachusetts at Amherst and the University of Durham. The data conclusively demonstrates that the hoax is incorrect.

The hoax claimed that transposing letters within a word did not slow reading performance because we recognize words as whole shapes. The team led by Keith Rayner found that all kinds of letter transpositions slow reading speed. Transposing internal letters as shown in the original hoax resulted in a reading speed decline from 255 words per minute (wpm) to 227 words per minute. Performance was worse if the transposition included the beginning or final letters of a word.

	Example Sentence	Reading Speed
Normal	The boy could not solve the problem so he asked for help.	255 wpm
Internal letters	The boy cuold not slove the probelm so he aksed for help.	227 wpm
Final letters	The boy coudl not solev the problme so he askde for help.	189 wpm
Beginning letters	The boy oculd not oslve the rpoblem so he saked for help.	163 wpm

Additionally this study examined readers’ eye movements while reading these different conditions. They found that readers needed to spend more time fixating on words in the transposition conditions and made more regressive saccades.

This study only looked at letter transpositions of a single position, like the kinds used in the original hoax. I can only speculate how dramatically reading speed would be hurt with more dramatic transpositions like:

The boy cluod not svloe the pelborm so he aeksd for help.

Hopefully this study puts the hoax to rest. This and many other studies have made it clear that we don’t recognize words by whole shapes, but use letter information to recognize words.

Cheers, Kevin Larson

Rayner, K., White, S., Johnson, R., Liversedge, S. (2006). Raeding Wrods With Jubmled Lettres; There Is a Cost. Psychological Science 17(3), 192-193.

Typography Tip #3.

Changing the line spacing in your document can have a dramatic effect on the how your page will look, whether it’s a Microsoft Word document, a PowerPoint presentation or a Web page. The term ‘linespacing’ has now superseded what used to be known in typographic terms as leading. The visual results are the same regardless of the term used. Most Word processors, Web Layout programs, and all high-end Page Layout software will allow you to change the line spacing in your document.

What are the benefits of changing the linespacing? Does the software not know the best line spacing and set it automatically?

The answer is yes and no. All fonts have a built in default line spacing, and this is usually sufficient to produce a good looking page. However the default is not always perfect, and the amount of line spacing needed varies depending on the font you choose. For example the space between the lines may appear more open when the font used has a smaller x-height.

Try setting different values on some different fonts you use to see the difference it can make. In Microsoft Word you can do this by selecting the text you want to add the line spacing to, go to the Format menu – choose Paragraph and then look for the ‘Line spacing’ option. Word offers you a few choices here. ‘Single’ is usually the default. Next is ‘Double’. This type of line spacing is sometimes required in legal documents or term papers. I am unsure of the reasons for this, but I suspect it has more to do with how things were always done, than for reasons of improving the readability of the document. Students like it as it can turn a 5 page term paper into an impressive 10 pager.

The option in Word I prefer to use is the last choice, ‘multiple’. Setting this option allows for the line spacing always to be a multiple of the point size you are using, so changing the size of the text in your current document will not result in line spacing that is too tight. This option also allows for the finest control, and can be edited to be 1.1, 1.2, 1.3 etc.

Here is a sample of the font Georgia at 10 point, set with default Single linespacing and then set with the multiple option set to 1.2

The difference here is quite dramatic and can open up the look of your document and make it more readable. Along with good margins and good letter spacing, appropriate line spacing can help towards the goal of making a page with much more even ‘typographic color’. In PowerPoint, following the same steps as above can help improve the line spacing in your presentation.

Mike

Introducing Ambiguity

Here is another idea for a sentence end punctuation. I call it the ambiguity mark. It is perhaps not as necessary as the irony mark; but unlike the irony mark, it has an elegant design.

I found this symbol in G.G. Neill Wright’s 1952 book The Writing of Arabic Numerals. It was written by a Papal Chancery hand of the 15th century and may plausibly be interpreted as 0, 3, 6, 7, or 8.

When would one use the ambiguity mark? It’s not intended for unintentionally ambiguous writing, as it would be better for the author to rewrite the sentence. The most compelling use would be for puns. Here is a classic font pun:

A font walks into a bar; and the bartender says: “We don’t serve your type here”

Kevin Larson

Another must have!

and of course another favorite for all things typographic is The Elements of Typographic Style by Robert Bringhurst. (If you can get the Hardcover, it is worth it, red ribbon pagemarker included)

I promise you will find this to be an invaluable reference for matters relating to type design and typographic layout.

Mike

Recommended Books for Screen Typography #1

There are several books that we’ve found extremely valuable in this group that deal with topics related to type on screen. Some are technically oriented and others are typographically oriented.

I’ll start off today with a technical book that is unfortunately out of print.

Digital Typography: An Introduction to Type and Composition for Computer System Design by Richard Rubinstein. Published by Addision-Wesley, Reading, Massachusetts, 1988. ISBN 0-201-17633-5.

The book is organized in two parts, the first on individual letters, and the second part on lines, blocks, and pages.

I highly recommend this book if you can get your hands on it.

Greg

Introducing the Irony Mark

Despite the less than positive comments for the Interrobang, I would like to advocate for more sentence-end punctuation options. I spend a lot of time communicating in writing with email and IM, and wish I had more options for expression. Take the following example:

Friend: Britney is planning to have another baby to save her marriage with KFed.
Me: God Bless America

What is the proper punctuation mark for my response? A period might be appropriate if I thought it was a good idea to rely on a baby to resolve marital difficulties, and an exclamation mark if I was feeling enthusiastic about it. A question mark might be appropriate if I had no opinion on the matter. Even the interrobang isn’t right here, I need something far more sarcastic.

I need a mark that clearly conveys the ridiculousness of such a plan. Without it, my intentions may be misread by a reader who doesn’t know me well. I’m not the first to advocate for an irony mark. Such a mark has already been invented as a backwards question mark. Unfortunately the irony mark does not appear in the ClearType font collection.

I foresee a future where I exclusively use the irony mark for punctuation

Kevin Larson

Interrobang?! — Interrobang!?

One of the least heralded, but arguably most important new features of the new ClearType font collection is the support for a previously little used character—the interrobang. This character was developed in 1962 by Martin Speckter with the intention of conveying additional information for advertising text.

People have many different opinions on this character. The reactions have varied from, “You want to add what character to the fonts‽” or “Cool, when will I be able to use it in the font‽”

These fonts are not the first fonts that Microsoft has worked on that support this character. Other fonts include Arial Unicode, Palatino Linotype, Lucida Sans Unicode, Frutiger Linotype, and Berling Antiqua.

Here is a look at the interrobangs in the new ClearType font collection.

Greg

Note: if in the above sample sentences you see a rectangle, that is not the shape of the interrobang. That just means the font being used in your reader or browser doesn’t support the interrobang. If you are using Internet Explorer with font embedding, you should see the correct character.