Recent posts

  • Relative readability Why go so big on type? There’s a short answer and a long answer.
  • Excuses, excuses Some people might suggest it’s not worth redesigning a site I only post to twice a year. They’re missing the point.
  • The Optimizer Every designer is wired differently. Some people are idea people, some people are artists. I’m an optimizer.
  • Indistinguishable from magic I love video games. I’m terrible at most of them. But I’m a sucker for a game with a good story.
  • Airport express Recently I learned two things about interaction design and user experience from waiting in lines at the airport.
  • Shouts and echoes There have been some situations lately that have got me thinking a lot about the Internet as a megaphone for personal communication.

Archives

16 March 2007

The problem with pixels

Relative font sizing is great, but it can get messy quickly. Now that IE6 is on its way out, is it safe to start talking about using pixels again?

Jeff made a good point at the typography panel at SXSW, which I missed, but he conveniently summarized (and clarified) what he said in a recent post on his site.

It has become somewhat of a sacred cow to say, “pixels are bad for text sizing—don’t use them.” But the reality is that there is nothing inherently wrong with sizing text using pixels. There is only something inherently wrong with Internet Explorer 6’s implementation of CSS, which doesn’t allow for text resizing when the fonts are sized in pixels. I think it’s important to understand—especially now that IE7 is out and text resizing is no longer an issue—that this is not a problem with CSS. Shout it from the rooftops: It’s okay to size text in pixels!

This is something Jeff and I have talked about before, and I wholeheartedly agree with his point. It also illuminates two related points that have been bouncing around in my head lately.

So long and thanks for all the glitches

First, IE6 is effectively deprecated. Its maker has acknowledged its flaws (some of them, at least) and addressed them in a new official version. IE6 is still out there, and the numbers are still significant enough that we still have an obligation to support it, but it’s on its way out.

The nice thing about something being deprecated (you know, like font tags) is that it’s a known quantity. There will be no new updates to IE6 (other than critical security patches, I imagine). All the bugs, quirks and inconsistencies we’ve come to know and love are going to stay exactly the same, from now until IE6’s user share dwindles. It happened with Netscape 4, and for most of the Internet, it’s happened for IE5. We still need to keep it in mind (for now), but I think we can start to (carefully) move past its limitations.

Design for the ideal, build for flexibility

The second point is less concrete—more of a loose operating principle. Lately I’ve been thinking a lot about the balance between control and flexibility in design. On the web, we tend to favor flexibility over control. I think this is partly a capitulation to the constraints of the medium (we avoid relying on 100% pixel-perfect layouts because they’re harder, and often to a degree not worth the results) and partly an acknowledgment of accessibility concerns (we create more flexible designs because they scale better to the myriad environments and alternative devices we need to support).

The principle I’ve been operating from recently boils down to this: design for the first page load in an ideal environment, while allowing for flexibility in non-ideal, unintended and user-modified environments.

One example of this in practice would be line-lengths. We can’t predict how lines will break in different browsers on different platforms with different font substitutions. But there are some cases where we can’t get away with just ignoring line-lengths altogether and letting things fall as they may. What I do in practice—and I think this is pretty common—is to optimize the way lines break (and widows and orphans) for the typeface and browser where I’m doing my primary testing and make sure it doesn’t completely fall apart in other browsers or when the text scales up or down. So the design ends up looking pretty much exactly how I intended in Safari and Firefox on a Mac, and reasonably close in the other browsers that matter. Which in my opinion is better than looking not quite how I intended in every browser.

Complex relativity

This only really works when I can at least control the text size at the initial page load. The reason I keep coming back to pixels is the same reason I’ve avoided them in the past: they’re fixed. They’re a known constant. I’m a big fan of reducing complexity, especially when you’re designing systems for larger sites or teams. The more variables you introduce, the more complex things get—it’s unavoidable.

Even when you’re using relative font sizing, you still need a reasonably constant base value to start from. A lot of people (notably, Richard Rutter) have done a lot of work to come up with a way to emulate that constant using percentages. And it works really well. I’ve built entire sites based on ems for sizing everything, even down to images.

In the simple case, with minimal nesting and complexity, the math is actually pretty simple. Say you’ve got a base text size of, say 10px (1em) and you want your header to be 18px. Easy, 1.8em. But what happens when you add a span with class=“quiet” within that header and you want it to be 15px. That’s tougher, since 1em now equals 18px, so you end up with something like 0.8333em. And what if there’s something inside that? One em now equals 15px, so you have to divide by that. It’s a slightly exaggerated example, but you can see how it can get messy very quickly.

So you end up either adding complexity to your sizing math and rules to handle the special cases—which makes your CSS that much more complicated for you or anyone else to figure out later—or you limit what you can do with your design up front. I’m all for embracing constraints, but I also don’t think the design should be dictated by the technology. So either outcome is less than optimal.

I think anybody who’s ever built out a relatively complex design using ems will agree that at some point they wondered if the benefit was really worth the effort. It all comes back to that same balance between control and flexibility. It’s an important balance, and the debate between pixels and ems for sizing text on the web hits right at the heart of it.

Two steps forward, one step back

There’s really not a good precedent for this outside of web design. If you read a magazine, book or newspaper and you need larger text, the best case scenario is that they offer a large print version. This requires a non-negligible effort and expense for you and a big expense for the publisher and is therefore pretty rare. On the web, the worst case scenario is that you need to download a new (free) browser because the one you’re using doesn’t support scalable text and the designer has chosen to use pixel sizing. There’s no way to paint this as anything but a giant leap forward.

When 90% of your users were using a deficient browser that didn’t support scaling of pixel-sized text, the decision was clear. Even if 5% of that 90% needed larger text, that was still significant. It was simply irresponsible to choose to use pixels for text-sizing as long as there was a workable alternative.

But the numbers are changing. IE/Win is no longer synonymous with IE6. And IE7 supports text zoom – the deficiency inherent in IE6 has been corrected by the browser maker. As IE7 takes over more and more of the IE/Win browser share, the decision to avoid pixel sizing becomes less and less of a sealed tomb. If there is a potential value in using pixel sizes (and I believe there is), eventually in some cases that value will exceed the value of catering to a diminishing percentage of the audience (and fraction of that audience at that). As that happens, it’s worthwhile to reevaluate some of our assumptions.

Pixel measures for font sizes, just like min and max-width, are part of the CSS spec. They’re both equally valid techniques from a standards point of view. The only reason we’ve avoided using either one is because the overwhelming majority of our audience aren’t using a browser that supports them properly.

In either case, the lack of support isn’t disastrous, just undesirable. If we use pixel font sizes, our sites are still accessible, just not as accessible in a particular environment as we would like. And if we rely on min and max-width, our layout is still usable, just not as usable in a particular environment as we would like.

When that environment accounts for 90% of our users, it’s not really realistic to deliver an undesirable result to that entire group. But what happens when the number is 50%? Or 5%? If we were willing to hide all CSS whatsoever from Netscape 4 when it was hovering below a 5% share, when are we willing to let one or two relatively minor features degrade? If the worst case scenario is really just a matter of degrees, when is it OK to just let it go?

Something to talk about

I haven’t settled on a definitive answer in my own head, and I don’t have meaningful browser share numbers to back it up if I did. Internet Explorer only counts for 19% of the total traffic to this site (12% IE6, 8% IE7, 1% IE5.5), so that audience is hardly representative. Even with broader numbers, it might still be too early to accurately pinpoint the rate of adoption for IE7 in a meaningful way.

Even in advance of the numbers, I think it’s a worthwhile conversation for us to have as a community to keep things moving forward. In the case of pixel units, I think there are pros and cons to relative and fixed methods, but I do think it’s worth having all the tools in our belt that we can, and know how to use them responsibly.

Agree? Think I’m off base? As always, respond in the comments or on your own site and lets get the conversation started.

Comments

  1. 17 March 2007

    kyle

    Thanks to Yahoo’s CSS library, I’ve started using ems instead of pixels. I agree that there’s no big benefit to one or other, but while IE6 is on the way out, it’s still going strong.

    Here are some month-by-month numbers from a consumer-focused site that see a fair amount of traffic… (in any given month, IE accounts for ~79% of total visits.)

    VisitsIE6IE7
    Dec ‘062.4M81.7%17.4%
    Dec ‘063M66.9%32.3%
    Jan ‘072.7M59.7%39.8%
    Feb ‘072.4M53.9%45.3%
    Mar ‘071.5M52.2%47.1%
  2. 17 March 2007

    Wilson Miner

    Thanks for the numbers, Kyle. The rapid trend toward about 50/50 IE6/IE7 is about what I expected. I imagine it will hover there for a while.

    A readymade CSS framework like Yahoo’s takes some of the pain out of relative sizing for sites that follow the pattern (and it’s very admirable of a site on their scale to take on that challenge), but the points above still apply once you step outside the common cases frameworks are designed to handle.

  3. 2 April 2007

    César

    IE7 resizes pages, not fonts (if they are specified in pixels): the only way to get a bigger text size is to increase the size of everything, because the ‘text size’ menu items won’t work.

    Take a page designed to be shown in a 1024 pixel wide window, in a 1024 pixel wide screen: if you want to increase the text size, you have scrolling, wich is not necessarily easy.

    IE7’s zoom is wonderful, IMHO, but it does not completely solve the accessibility question…

  4. 2 April 2007

    Jim

    The problem with px fonts is that they bear absolutely no relation to my chosen font size. I think it’s ludicrous to worry about small things like where exactly line-breaks occur in the text when you aren’t paying attention to this basic requirement for readability.

    No, resizing isn’t good enough. I don’t think it’s reasonable to have to resize my text on every site because everybody has a different idea about what’s readable.

    No, minimum font sizes aren’t good enough. I don’t think it’s reasonable to throw away the visual cues you get from differing font sizes in the same document (you do make headings bigger than normal text for a reason, don’t you?)

    100%/1em font sizes work properly. They are guaranteed to be readable. You say “design for the ideal, build for flexibility”. Well the ideal, where a user has chosen a particular font size, it’s simply not possible to do better than use 1em. And as far as flexibility is concerned, of course 1em is the most flexible.

  5. 2 April 2007

    pauldwaite

    “IE6 is… on its way out”

    Hopefully, but if Windows 2000 hangs on (e.g. in businesses), then so will IE 6, as IE 7 doesn’t run on anything less than XP.

    “IE7 supports text zoom — the deficiency inherent in IE6 has been corrected by the browser maker”

    As Caesar said, no it doesn’t. It supports page zoom. Text zoom increases the size of the text, whilst keeping every other dimension the same. Page zoom makes everything bigger, which can introduce horizontal scrolling (even, in my experience, on fluid width sites - try the Google home page).

    I’m not saying using pixels for font size isn’t an acceptable trade-off, as your points about complexity for sites with lots of different font sizes are spot-on. But I think you’re playing down the continuing problem with IE 7.

  6. 2 April 2007

    Wilson Miner

    Jim, that’s a good point and one that I almost included in the original piece. The balance I talked about between control and flexibility is also a balance between designer control and reader control.

    I understand the accessibility argument for user control trumping designer control in all cases because it’s not safe to assume otherwise. I’ve adhered to that for a long time because it has been the prevailing precedent on the web. But it’s not the precedent from any other medium in the history of design. Books don’t have reader preferences for font sizes, but they do have accepted guidelines which good book designers understand about what sizes, typefaces margins and line-lengths encourage readability. And bad book designers ignore or don’t understand them and ugly, unreadable books get published every day. I’m not saying this is something to strive for, but it’s reality.

    I think a lot of designers would argue that aesthetic qualities also have an effect on readability. And from an aesthetic perspective, letting the user choose the text size is far from ideal. If I have to create a design that works equally well given any range of font sizes a user might choose, then my options are limited as far as the complexity of the design I can create. And arguably, the design will be less successful in any environment because it must be equally successful in all environments.

    I’m not in any way suggesting that we should reverse the equation and designers’ font size choices should always trump the users’, or even that pixels are the right choice for most site designs. I’m just arguing that, as long as the user retains ultimate control, it’s a valid choice for a designer to retain some control over font size and text flow in their designs.

    Again, it’s a balance. We’ve skewed to one side of the balance in our industry for a while. I’m not saying we should skew the other way, but that it might be time to recalibrate a little bit.

  7. 2 April 2007

    Wilson Miner

    Paul, I very well may be playing down continuing deficiencies in IE7. Since I don’t use IE every day as my primary browser (and in fact avoid it at all costs except for testing), so I’m certainly not qualified to give the “all clear”. I’m operating under the (probably optimistic) assumption that the Text Zoom feature was directly implemented to address the resizeable text issue and based on some cursory tests seemed like at least a reasonable solution. I may very well be wrong, and we may be in for another dark age of catering to IE’s quirks and deficiencies.

  8. 2 April 2007

    Rumble

    One useful tool I use when using ems for text size is the very handy em calculator, a small javascript app available online at:

    http://riddle.pl/emcalc/

  9. 2 April 2007

    Jim

    Books don’t have reader preferences for font sizes

    Actually, they do quite a lot of the time. Head down to your local library sometime, you’ll find it’s quite common to offer a “large print” edition, even if they aren’t on sale in normal bookshops.

    But more importantly, the reason why many books don’t have reader preferences is because it costs more to cater to different font sizes, not because it’s a bad idea. That isn’t true about the web - not only does it not cost anything to cater to different preferences, but it’s actually the default - you have to go out of your way to lose this advantage over print.

    I think a lot of designers would argue that aesthetic qualities also have an effect on readability.

    Of course that’s true. But to the extent that aesthetics matter, they are always trumped by readability. I don’t care if a page looks pretty if I have to fiddle with my browser settings to read it. If I have to do that, then the designer has failed. That is what separates design from art. Design’s goal is to present things clearly and appropriately, not to look good for the sake of it. If you’re choosing aesthetics over readability, then you’re not a designer, you are an artist.

    If I have to create a design that works equally well given any range of font sizes a user might choose, then my options are limited as far as the complexity of the design I can create.

    If somebody can’t read the text, they are either going to fiddle with their settings to increase the text without your blessing (and have your design break) or they are going to leave without reading. Either way, the fact that your design isn’t compromised wins you nothing.

  10. 2 April 2007

    Wilson Miner

    Jim, I think if you read back through you’ll find that I addressed each of your points in the original post. I think you may be arguing against points that I’m not making, but I’ll just expand briefly here for clarification.

    the reason why many books don’t have reader preferences is because it costs more to cater to different font sizes, not because it’s a bad idea. That isn’t true about the web — not only does it not cost anything to cater to different preferences, but it’s actually the default — you have to go out of your way to lose this advantage over print.

    I think there a few reasons why this is a false economy. Yes large print editions exist, but they are relatively rare because they cost more to produce. And the prohibitive cost isn’t just because it costs more to physically print alternate editions. It also costs more for someone to design that edition, taking into account all the constraints of a unique audience. This cost doesn’t go away on the web. Does that mean our audience wouldn’t benefit from a custom design for large text, or high contrast, or color blindness? Absolutely not. Is it trivial to create and maintain designs for all of these cases on the web? Absolutely not.

    I’m not at all arguing that users shouldn’t be able to adjust font size. No designer or browser maker should try to prevent them from doing so. The fact that IE6 does prevent them from doing so based on how the font-size is specified is a flaw that no other mainstream browser exhibits. There’s nothing about pixels units in the W3C spec that says they shouldn’t be scalable after the page loads. As that browser flaw is addressed, hopefully the specification can be used as intended.

    …to the extent that aesthetics matter, they are always trumped by readability. I don’t care if a page looks pretty if I have to fiddle with my browser settings to read it. If I have to do that, then the designer has failed. If you’re choosing aesthetics over readability, then you’re not a designer, you are an artist.

    I absolutely agree that readability is a major component of aesthetics in a functional design. They shouldn’t be in conflict and I’m not arguing that one should trump the other. As I said, it’s a balance, and one that a good designer is intimately aware of. I’m not here to apologize for bad designers, or artists for that matter.

    If somebody can’t read the text, they are either going to fiddle with their settings to increase the text without your blessing (and have your design break) or they are going to leave without reading.

    Perfect, that’s exactly how it should work (except for the design “breaking” - it should degrade, hopefully gracefully). I get to deliver a design that renders as I intended it for a majority of my audience, and every user is able to adjust as needed. Design for the ideal, build for flexibility. I’m missing the part where I excluded compromise or demanded tribute from those who dare to increase the text size.

  11. 2 April 2007

    Jeff Croft

    That isn’t true about the web — not only does it not cost anything to cater to different preferences, but it’s actually the default — you have to go out of your way to lose this advantage over print.

    Sorry, but this is a 100% bogus statement. It does cost something to cater to different preferences on the web. What does it cost? It costs either quality of design or time and effort.

    It’s very, very difficult to achieve professional-level typography and account for all possible font sizes. With a great deal of time and effort you can get pretty darn close to professional-level typography at all font sizes — but only if you use relative sizes, which means much more complicated math and dealing with a lot more browser inconsistencies. This adds up to a lot more time and effort.

    If you insist upon text resizing in IE6, you insist upon one or the other: average, “default” typography, or a lot of extra work. Unless you can say you’ve built huge sites in all relative units that maintains the level of excellence in typography that Wilson’s employer insists upon (hint: their logo is a fruit and they sell computers), then you may not have the experience to understand. Only sizing in pixels gives the designer this level of control without requiring a bachelor’s degree in long division. Period.

    Now, let’s talk about IE7. Yes, page zoom is not the exact same thing as text zoom. But does it allow one to resize their text? Yes. Does it sometime incur horizontal scrolling? Yes. Is that an accessibility problem? No! Don’t confuse accessibility with convenience. It may not be convenient to have to scroll horizontally, but it’s certainly accessible.

    We have to keep things in perspective. Yes, we should be as accommodating as possible to folks who have special needs. But, in the real world (where both Wilson and I design web sites for a living), there are resource constraints. I don’t always have the time to size everything in relative units to account for the increasingly tiny percentage of users for whom absolute units are problematic.

    How tiny is that percentage today? Well, on our newspaper sites, we’re down to almost 35% of visitors using browsers that can’t resize text sized in pixels. Of those 35%, how many need to resize text? Hard to say for sure, but it’s fair to assume the number is quite low, especially considering our sites default to large-ish type as it is. Let’s say it’s 5%. Now, of that 5%, how many are unable to upgrade to IE7 or Firefox? Almost none. Almost certainly less than one percent of our readers can’t resize text set in pixels if they need to.

    Wilson is right. We’re almost to a point where this is a non-issue. People just need to keep in mind the fact that using absolute-sized text is not a problem in CSS — it’s a problem in one crappy browser, and that browser is on it’s way out the door.

  12. 5 April 2007

    Andrew Maben

    “Does it sometime incur horizontal scrolling? Yes. Is that an accessibility problem? No! Don’t confuse accessibility with convenience. It may not be convenient to have to scroll horizontally, but it’s certainly accessible.”

    Tell that to someone who is both visually and motor impaired and is trying to read a long article, every single line of which extends beyond the width of the window. Sure it’s “accessible” on the most basic level, in that it’s not impossible to read the article, but that line of argument ends with wheelchair ramps being unnecessary because, hey, why not just let the disabled crawl up the stairs?

  13. 5 April 2007

    Jeff Croft

    Tell that to someone who is both visually and motor impaired and is trying to read a long article, every single line of which extends beyond the width of the window.

    Sounds pretty inconvenient. Certainly not inaccessible, though.

    …but that line of argument ends with wheelchair ramps being unnecessary because, hey, why not just let the disabled crawl up the stairs?

    No, it doesn’t. That’s the wrong analogy. Suggesting that people with low vision should be able to read content exactly the same way as those without is like suggesting that people in wheelchairs should just walk up the stairs. That’s ridiculous. People in wheelchairs will never be able to get around a building the same way as people with no such disability. That’s unfortunate, but it certainly isn’t an accessibility issue. Likewise, people who have low vision will never be able to read small text on a screen without a slightly different process than people who have great vision. That process may include zooming in on a page, and it may include scrolling.

    I have five programs (besides my browser) open now: Finder, iTunes, Photoshop, and TextMate. Each of them have a horizontal scroll bar showing. Does that make them inaccessible? I don’t think so. In fact, the sole purpose of those scrollbars is to make me able to access content that doesn’t fit on the screen. The entire reason scrollbars exist is to make things accessible.

  14. 6 April 2007

    John Faulds

    Jeff, you say that horizontal scrollbars aren’t an accessibility issue but one of convenience, but if you’re one of those motor impaired people that Andrew refers to, that inconvenience may quickly turn into an accessibility problem.

    If horizontally scrolling back and forth causes you so much incovenience (or even actual discomfort) that you give up on a site and can no longer continue to browse it, I’d say that’s an accessibility problem.

    Sure all programs may have horizontal scrollbars, but how often do you actually use them in a way that require constant horizontal scrolling?

    I personally think IE7’s text zoom implementation is wrong especially when compared with how other browsers do it.

  15. 9 April 2007

    Martina Oefelein

    Books don’t have reader preferences for font sizes, but they do have accepted guidelines which good book designers understand about what sizes, typefaces margins and line-lengths encourage readability.

    Yes, but book designers don’t have to cope with different screen resolutions. Letters in a book will have the same (well-designed) size everywhere regardless who reads the book, and where. The same is not true for web sites. The same 12px Lucida Grande text looks substantially smaller on my 13” MacBook than on the 15” monitors in my office. A text that looks OK on the latter may be uncomfortably small on the former.

    And this problem will increase over time as manufacturers adopt higher-resolution screens.

  16. 9 April 2007

    Jeff Kenny

    I’m gonna have to go with Jeff on this one. Whether or not something is accessible is NOT a subjective argument. Saying something is inconvenient is adding a subject element to the argument.

    “Letting the disabled crawl up the stairs” isn’t, as Jeff said, a valid analogy. BUT, say for instance the 10th floor of a building was only accessible via elevator by going up to the 15th floor and then switching to another elevator to go down to the 10th floor. Sure, this isn’t convenient but its certainly accessible.

    And for the record, I use the Finder in OS X almost exclusively in column view and as such use the horizontal scrollbar constantly. It causes me no discomfort or inconvenience.

  17. 12 April 2007

    Alex M

    I have to agree with Martina (post 15) about the screen resolution issue. This is the main reason why I believe there should be some flexibility in web site design when it comes to font size and page width. Most people resort to lowering their screen resolution, but I think there should be a better way.

    I read Dan Cederholm’s “Bulletproof Web Design” a while ago, and I was quite fascinated with the idea of making web layouts that don’t break when resized. He shows techniques for creating layout elements that don’t break, many loosely based on the Sliding Doors technique, which is cited by the book. I was quite disappointed, though, to see that very few sites today actually take any of the advice given in the book.

    I was wondering if anyone here has read the book and has any opinion about it, because I’m starting to have doubts myself about whether it’s worth it to make website layouts that are, well, bulletproof.

  18. 12 April 2007

    JD Graffam

    @Alex M: Bulletproof is good to keep in mind, but always determine how bulletproof to make something using your own best judgment. Personally, I think Dan C.’s point is less about being bulletproof and more about being bullet-resistant. Sliding doors, for example, does break at a certain point.

  19. 12 April 2007

    Alex M

    Of course I don’t mean that a “bulletproof” site won’t break. All I was saying is that it seems most people don’t even make the effort. The layouts are completely fixed. If you were to go to a random website and increase the font size just one notch, chances are very good that the layout will break.

    With the lack of sites that adjust to increased font sizes, I was starting to wonder if it’s worth it to use some of the techniques from the book in the real world, since most sites don’t use them.

    I know this is probably going to be a matter of opinion, but it makes me wonder about the pros and cons.

  20. 12 April 2007

    Wilson Miner

    I think it’s important to make the distinction between sites that actually adapt the layout as you size the text up or down (e.g. by using em values to set the width of content areas) and sites that allow for text to be sized up and down within a fixed layout without becoming unreadable.

    I usually borrow a trick from photography called exposure bracketing where you shoot the same photo at one exposure as well as one or two notches above and below the main setting.

    So in any layout, I try to make sure the copy is readable and the navigation works two clicks above and below the base font size. It doesn’t have to always look pretty, but it should work. If it still works outside that bracket, great, but I won’t spend a lot of time worrying about it if things start to overlap or disappear.

  21. 16 June 2007

    NewsBlues

    The average surfer doesn’t know that there may be better browsers than IE. For the most part, he doesn’t need to know.

    However, isn’t it reasonable to assume that disabled people would acquire a special set of skills, and an enhanced knowledge of certain aspects of the world, to help them cope with their disability? For example, they may need to know more about wheelchairs, or head-mounted computer mouse substitutes, or how different doors function, or how to find the cargo-loading entrance to buildings so as to avoid even one or two stairs. I’ll bet they do know more about lots of things than most people do.

    It seems to me reasonable that knowing that they shouldn’t be using IE, that the proper browser for the disabled is FireFox or Safari or just about anything except IE, is a reasonable expectation — part of their special-knowledge toolkit. But anti-pixel-sizing web purists always talk as though the disabled should be expected to have no more knowledge of what browser to use than the general public does.

  22. 16 June 2007

    Terrence Wood

    I’m not sure the what the point of Jeff’s article is apart from restating that IE6 doesn’t resize text set in pixels and IE7 does. He claims that ems and pixels (or all units, in fact) are equal, and goes on to say that he is not advocating sizing text in pixels (see comment 26).

    There is a good reason to not size text in pixels: ems and pixels are not equal units. An em is determined by the browsers default font size which can be adjusted by the user and/or the designer on the fly - everything sized in em’s is relative to the font-size you start with. Pixels describe the physical dimensions of the display - Larger, newer monitors have higher resolutions (there’s more pixels and they are smaller) than older monitors.

    See half way down: http://en.wikipedia.org/wiki/Pixel, and for an interesting developer POV see: http://alexking.org/blog/2006/04/11/pixel

  23. 30 June 2007

    Barack

    As long as YOU are consistent in your own designing and coding of websites, you’ll have an much easier time changing or converting your structure if the need comes about. On the otherhand, if you use a mix of both px and pt, and mix many other standards, etc, you might need to take a few tylenol before sitting down to your desk to update your site. Consistency is the key.