Everyone’s excited about the new iPhone “Retina Display”, which has 960×640 resolution. That’s about 326 dots per inch (dpi). Most desktop monitors give you 100 dpi or less, so it’s a great improvement.
Though that’s impressive, it’s nothing compared to the resolution of newsprint text, which is somewhere between 300 and 1000 dpi. Even cheap laser printers crank out 600 dpi black-and-white text.
The iPad is a 132 dpi device. When it, and other ebook readers, start to approach the print quality of a smudgy newspaper, maybe we’ll be able to read the damn things all day without squinting and getting headaches.
Comrade Jake
All I know is, the iPhone can’t come to Verizon soon enough. And yes, I’m aware that it’s not likely to be anytime soon, thanks.
sherifffruitfly
Does the new iphone do/have anything that the evo doesn’t already have/do?
jurassicpork
Mike Flannigan weighs in on the Redoubtable Thomas and the rank hypocrisy it’s unleashed in the MSM.
pharniel
preach it!
Turbulence
In my experience, eye-strain does not come from low resolution displays per se. Eyestrain comes about from having a ton of bright light poured into your eye balls. Paper is reflective; electric displays are transmittive.
The Kindle doesn’t have such hot resolution but it doesn’t cause me eyestrain. The difference is that the Kindle has an e-ink display so it is reflective like paper rather than transmitive like the iPhone/iPad and every other computer display.
thomas Levenson
Big difference between the iPad and newsprint to these fifty year old eyes (50 w. a tailwind, that is): I get to choose the font size.
I’ve got an 11th edition Encyclopedia Brittanica that I use as my insomnia cure; it’s great – I learn weird stuff while drifting back to sleep. But my compact edition copy has two type faces: small, (roughly newspaper size) and much smaller. My eyes hurt after a while. Ditto the Sunday Times — I couldn’t read that all day without getting a headache.
My iPad — hell, my non-retina display iPhone, properly sized for the state of my eye muscles, works great all day. I read Grant’s memoirs on my phone on a Boston-LA flight last month, just about the whole way. Works a charm.
I write books; I love print; I also love technology that I can manipulate to my needs/desires of the moment.
Lee
@Turbulence:
This is very true.
The Kindle (and other eReaders) that use ‘digital ink’ have little to no eyestrain because of the way they display text.
It has very little to do with resolution.
cleek
the resolution of newsprint figure is a bit misleading. yes, the device which creates the plates that are used to print the newspaper might have 600 dpi, but with the grainy, porous, uneven paper, the cheap smudgy ink, and the need to crank out thousands of copies every day for as cheaply as possible, they can’t really render those 600 dots.
laser printers do a better job, but most are just plain black – no grays. and grays let you do anti-aliasing, which increases the apparent resolution.
in any case 300dpi in full color is pretty impressive.
ellaesther
Oh mistermix you have made me so happy! I love print so much, and now this bit of information arrives to send me off into my day with a smile.
Tractarian
Wait a minute. 326 dpi is “nothing compared” to newsprint text? And newsprint text is “somewhere between 300 and 1000 dpi”? Isn’t 326 somewhere between 300 and 1000?
I don’t know what’s making your eyes hurt, but I can tell you that this post made my brain hurt.
Seth
I don’t the exact dpi of the eink screen on my Nook (Barnes & Noble) but it reads much more like actual paper/text than my laptop screen of iPhone screen. Being able to change the size of the text AND not being backlit, I don’t even notice that it’s a screen.
My two cents.
Jason Bylinowski
The iPhone and really all smartphones are just still way too expensive for my modest salary. I thought I might get a blackberry because they are so ubiquitous now that they are free with contract. But a Droid or IPhone, which are admittedly very cool and would be a lot of fun to have? They just cost too much to justify payment even if, technically, I can afford it. Plus, the warranty on them sucks.
edit: grammar
cleek
@cleek:
(at least this was the case when i was taking all those printing classes. newsprint and ink may have radically improved in the last 20 years)
dmsilev
I dunno. I’ve read several books on my iPad, and haven’t noticed any eyestrain issues. Sure, higher resolution is always nice, but for my eyes at least, the current generation of devices is Good Enough.
dms
Gromit
Last a full day on a single charge?
mistermix
@cleek: Phototypesetter resolution is ~2400 dpi, so that’s the point from which degradation starts. Crappy paper and a crappy press do degrade that, as does laser printing on cheap paper.
@Tractarian: You’re right that “nothing” is a bit hyperbolic, but 300 is low of the the low end of a shitty press. Good printed material (e.g., a magazine) is much higher than that.
Hob
@mistermix: Yeah, but you’re mixing up black & white resolution with grayscale resolution, so the comparison makes no sense.
Beauzeaux
@Gromit:
Really? My EVO is lasting more than two days on a single charge, thank you.
Charity
@thomas Levenson: My husband’s got a visual impairment (ocular albinism), and he loves being able to adjust the text to the size he needs. It’s even better on the iPad than on the iPhone.
mistermix
@Hob: The numbers I’m quoting are b&w res, not greyscale. Read the links, e.g.,
DanF
@Turbulence: Turbulence gets this exactly right. Staring at an LCD display is like shining a dim light in your eyes. that’s what causes your eyes to hurt, not the resolution. Try reading a book in the bright sunlight. Same result.
cmorenc
@mistermix:
My notebook computer screen is 1440×900 pixels, spread evenly over a 12.75″ x 8″ inch area. That translates to a pixel density of total Pixels/Area (in inches) = 1,296,000/102 in. = 12,960 pixels per square inch. The limiting factor in readability isn’t the inherent display resolution of the contemporary generation of computer screens (many of which are now capable of showing true high-def video), but rather the quality of the graphics display software used to produce fonts, and how small or large the user chooses the default font size to be in e.g. their web browser or word processor.
Now of course individual pixels (which are the smallest discrete display elements of a computer monitor screen) and dots (which is a concept derived from the smallest discrete elements of ink a printer is capable of outputting) are somewhat analogous, but not truly equivalent. The operating system (in particular its graphical display software modules) & hardware graphical display controller determine how to build virtual “dots” of a specified density size from how many pixels each. Actually, the reading font is determined by what point size (average height of characters) the user specifies, modified in practice by the characteristic shape and size of a given stylistic font (not all of which appear to have the same uniform character height at a given font point size).
In part, readability on a computer monitor is greatly enhanced if the user chooses a font made for readability, rather than one made for style. Certain fonts that were ideal for mechanical typesetting (Helvetica, New Times Roman) that were imported to computer screen defaults from the printed page context (because users were accustomed to thinking of these as acceptably readable fonts) actually aren’t as ideal for computer screens as plainer fonts with cleaner pixel lines, such as Ariel (a vastly better font IMHO for computer screens and digital printers).
Try experimenting with your default font type and size settings – it makes a huge difference.
blahblahblah
Buy an eink ereader if you want extended reading on an electronic device. Over the years I’ve bought a Sony PRS 505, an iRex Iliad, and most recently an Entourage Edge. The Edge can even display full page technical and scientific PDFs on a 10″ screen with excellent readability. It also allows for annotating with taking pen input.
The problem with reading on an iPad or a netbook is not the screen resolution, it’s the back lighting and refresh rate which tire eyes. eink has many problems and technical hurdles to overcome, such as lack of color and slow display updates, but for just plain reading it’s wonderful.
Corpsicle
@cmorenc: In english you have 114 DPI
Gromit
@Beauzeaux:
Usage patterns do matter, obviously.
cleek
@cmorenc:
just to clarify for those who might not know: DPI is a linear measurement, not an area measurement.
your monitor has something in the 112 DPI range (sqrt(12960)) , not in the 13,000 DPI range.
Hob
@mistermix: Yes yes yes, I know that. A lot of us here understand these things, OK? I’ve done graphic design for both print and screen. What I’m saying is that in what you wrote, you’re directly comparing a grayscale resolution of 326 dpi to a b&w resolution of 300-1000 dpi, and saying that the former is “nothing” because it’s a smaller number, and that’s just misleading and wrong.
Comrade Mary
I have fairly small hands, but found that typing on an iPhone, or selecting links on a web page, was rather frustrating. Can’t use a stylus because the screen needs body heat to register, I believe.
So if the screen is about the same size, but the resolution is finer, are people having problems touching links and typing? Do they have to zoom even more from the default display to actually do anything with the device?
burnspbesq
I have no difficulty reading for extended periods on my iPad. I haven’t tried reading on it at the beach, which I understand from those who have is a, umm, challenge, but for where I use it it’s fine.
And the commercials for the iPhone 4 are going to kill. The one that focuses on Face Time, and closes with the hearing-impaired lovers signing to each other, manipulates your emotions in ways that will be studied by marketing students for generations. Jobs, the bastard, still has an uncanny ability to suck money out of my wallet.
burnspbesq
@Comrade Mary:
Check back at the end of the day on June 24, which is the release date. I suspect I will be pre-ordering one and will pick it up at lunchtime.
Mister Colorful Analogy
@jurassicpork:
Thanks for the link. Great read; it deserves a post of its own.
MrCA
Beauzeaux
@Gromit:
Actually I have been using mine quite a lot since I got it Friday morning. Usage is far less important to extended battery life than is turning off the bluetooth and G4 antennas when they’re not needed.
Gromit
@Comrade Mary:
Webpages and interface elements will render at the same size as the original iPhone, just with greater detail.
Also, the keyboard, like any form of manual text entry, takes practice. I have fairly large hands, but I do pretty well with one-thumb typing in portrait mode on my 3GS. I almost never use the keyboard in landscape, since I’m not a two-thumb typist.
Sentient Puddle
Erm…I think comparing DPI in electronic displays to print is apples to oranges. Print is always higher. It’s the nature of the medium. When it comes to graphics, printers always used what seems like a ridiculously high resolution to the uninitiated for their digital copies.
So I don’t think this takes away from what Apple achieved with this display. Cracking 300 PPI on a digital display is still bloody impressive.
burnspbesq
Yo, mistermix, when was the last time you went to the ophthalmologist? Don’t blame the device unless you’re sure it’s not your eyes. Visual acuity changes with age. My presecription has changed the last three times I went for a checkup, and I’m sure it will change again later this month.
Brian J
I don’t feel like I am squinting that badly with the iPhone because of the phone itself. I think my eyes are just getting worse, and the fact that I don’t change my contacts often enough probably isn’t helping.
Anyway, will this new phone have 4G? Some say it won’t, but I haven’t been able to get a definitive answer one way or the other.
Corpsicle
@Brian J: No 4G, but 4G doesn’t really exist yet anyway.
mclaren
That’s the problem with all these digital widgets. They’re designed by twenty year olds for twenty year olds. You have to lick the damn screen to see anything.
Brian J
@Corpsicle:
What do you mean?
I don’t know if I’ve reached the point where I don’t need speed as much as I did. The 3GS seemed to be an improvement on the 3G, but does this new phone offer anything that would justify the cost? I am not sure that it does. I don’t use it for any of the cool applications besides Shazaam. The browser is incredible, but again, is any advance in speed really enough to drop a couple hundred bucks, especially if I am not due for an upgrade?
jimBOB
@Hob:
Hob is absolutely right. Straight B&W bitmaps show visible aliasing at much higher resolutions than color or grayscale. Directly comparing the two just demonstrates ignorance.
For most commercial printing, 300 dpi is the maximum resolution you could ever use for continuous tone subjects. Going past this is a mistake, as you’re pushing extra data for no benefit.
Tim
There’s also an effect from the amount of light produced by the display. Paper, and the Kindle, produce no visible light, and only reflect light. That’s easier on our eyes. They also have their text right on the surface, which helps.
The new iPhone will have the text much closer to the screen due to a new process for producing LCD touchscreens. It will help some, but not be as good as paper or eInk.
The amount of light can be fixed some, too. I regularly read long articles on my iPhone – New Yorker length – in the Instapaper app. One option it has is to produce the text as light gray text on a dark gray background. The contrast is enough to read but not so much that it’s glaring, and the reduced amount of light significantly reduces eyestrain. I often find long articles online, save them to Instapaper, and then read them on my iPhone. I imagine Instapaper will look even better on the new iPhone. (The developer has an iPad native version, too.)
Tim
@Brian J: I think that the A4 chip is going to be a significant improvement, far more than the 3GS was, if it’s the same chip as in the iPad. When I tried an iPad, I was struck by how much more responsive it was than my iPhone (3G, not 3GS). It loaded webpages much faster, it opened and closed apps much faster, and handled input much better.
The Moar You Know
Reading is for liberal faggots. I get all the information I need from the teevee. Maybe if you’d all pull your heads out of your asses and stop bragging about what smarties you are your weak eyes wouldn’t hurt so much and you could go on to more decent pursuits, like football.
We tried back in high school to teach you this as best we could by dunking the heads of you poindexters in the school toilets, but apprently none of you learned your lesson. Enjoy your early-onset presbyopia, nerds.
arguingwithsignposts
First of all, DPI =/= PPI (see here for an explanation). Comparing the two is a fool’s errand.
Second, the reason your eyes hurt is because you’re getting older, and you probably need reading glasses or a bigger font size on your browser.
Corpsicle
@Brian J: 4G refers to the speed of the cellular network, not the speed of the phone. 4G cellular networks dont really exist yet.
gwangung
For me, the new iPhone has some solid new features. But it’s not enough for me to upgrade from a 3GS. Think it would be different, though, if I had a 3G….
CalD
__
Last I knew, the standard resolution for low-quality imagesetting, e.g., for newsprint, was 1200 DPI. The downward limit is the line count (lines per inch, LPI, whatever) of the halftone screen used to reproduce photos and gradients.
To accurately represent up to 256 shades of gray, the ratio of the imagesetter resolution to the halftone screen has to be at least 14:1 (DPI:LPI) so 1200 DPI is sufficient resolution to do an 85-line half-tone in full grayscale (85 x 12 = 1190). That’s kind of a sweet spot because much below 85 LPI, the dots in the photos start to become very noticeable and the fewer shades of gray you have, the blotchier photos become. 256 is about the number of shades the human eye can discern.
In terms of text and line art, if you’re looking at film output you have to look pretty hard to see the difference between 1200 and 2400 DPI imagesetting and the difference is likely lost by the time you burn a plate and print it on low-grade stock such as newsprint. High-quality offset printing on coated paper can preserve enough detail to make the difference noticeable though and when printing on coated stock you normally use finer halftone screens. Magazines typically use 133-150 line halftones. I’ve seen coffee table books that went as high as 200.
But with all that said, one very important difference between a blob of ink or toner and a pixel in a CRT or color LCD monitor, is that ink and toner can’t change color. So comparing printer/imagesetter and LCD resolution is not an apples-to-apples comparison. In terms of effective perceptual resolution, when each dot can be pretty much any color the effective resolution for a given DPI is going to be some multiple of what you get when limited to a binary state. But I don’t know the numbers for that off the top of my head and there’s likely to be some gray area there (no pun intended) in any case.
kralnik
golly. i just found this blog, and am quite impressed with the quantity of on-topic give and take. wrote a paper on this topic some months ago and yes the research seems to agree with the entry 23 on “blah blah’s” entry.
small text for folks after 40ish as the eye loses its flexibility is tough. Therefore small spaces are necessarily worse since you struggle with fewer words at a glance.
secondly refresh rate is crucial and for “long form” digital ink is not getting the un-noticed flicker that distresses the eye for prolonged use. It is just so that staring at discursive symbol sets is best in certain conditions that we have refined since Gutenberg.
Thirdly, screens that have “back light” vs. reflective light are, as mentioned before, a different and more taxing experience on the eye varying with exact external environment.
Lastly, this is only for long form text, not for Cosmo articles, or pics of britney spears. so the debate goes to whether you are doing serious reading. And that is always better when more similar to traditional books. Thats why books got like they are: Hundreds of years of beta testing
Brian J
@Corpsicle:
Well, yes, but aren’t phones usually designed to take advantage of the networks they are on? If not, what’s the point of advertising a phone is 4G capable? I ask because I’m pretty sure I saw an ad for a 4G phone yesterday for Sprint.
@Tim:
If that’s the case, then perhaps I’ll get it. Anything that lets Balloon Juice load faster is okay by me.
Gunner Billy K
I’ve always suspected – but now I have proof – mistermix knows nothing about tech (and, in this case printing). This post is so dumb I can’t even begin to debunk it without sacrificing IQ points.
Please, John Cole, can this joker – or at least tell him to stop posting about technology.
Gromit
@Gunner Billy K:
Geez, that’s kind of harsh, don’t you think?
Tim
@gwangung: I have a 3G. While it’s a good phone for me, I’m going to let myself succumb to [email protected]Brian J: I think that Sprint is the only US carrier to have rolled out a 4G network anywhere. They have 4G coverage in Baltimore and a couple of other mid-sized cities.
It seems fairly confusing where it’s been rolled out – Portland, OR, and Atlanta, have it, too, but under the Clear brandname, which Sprint seems to own. It doesn’t seem like those networks are truly 4G as specified by the standards group that decides these things.
It seems like the 4G of the EVO 4G is mostly a marketing ploy for now until cell carriers start deploying actual 4G networks.
Corpsicle
@Brian J: Sprint has a very limited 4G network in a few cities. AT&T’s 4G is at least a year away, probably longer.
Uriel
@Gunner Billy K: Well, to be fair, the majority of people I’ve met that understand tech are absolutely clueless about printing, and vis-versa. Nor should they know both, particularly- they’re two very different fields for the most part.
About the only place where tech and print people really have a need for a common knowledge base is in print shops and newspapers themselves, where they work in tandem. And having spent several years in that field, I can tell you that even there- they don’t.
Mr Furious
This whole post is fatally flawed from the start.
If an iPhone display can actually display at a resolution of 326 pixels per inch it beats the shit out of any printed thing you’ve ever laid eyes on. Period.
Because of the apples/oranges numbers and terminology being tossed around here, it’s difficult to know exactly what’s what, but here are some facts for you based on twenty years experience in design and print publishing:
Newspapers are printed at 85 to 105 dots per inch.
Magazines at 133-150.
Really top quality coffee table books at promotional materials between 177 and 200.
And those numbers are what the printing plate represents—not what the final printed paper your eye looks at. Depending on the class of printing—”cold” ink absorbs into the paper, “hot” ink dries on the surface, the bleed and everything else, your eyes rarely look at anything as fine as the numbers stated above.
In the end, if the iPhone screen is actually rendering full color at 326 ppi, it’s going to be like looking at a goddamn photo—twice as sharp as most printed color material you’ve ever seen and four times sharper than the average monitor. In other word, fucking impressive.
terry chay
@Mr Furious: Small caveat numbers are from halftoning (for graphics, not text). That’s why they’re giving in LPI, not DPI. You are correct in spirit.
But you are correct with:
“In the end, if the iPhone screen is actually rendering full color at 326 ppi, it’s going to be like looking at a goddamn photo—twice as sharp as most printed color material you’ve ever seen and four times sharper than the average monitor.”
Of course, viewing distances vary in the monitor comparison.
My post (above) tries to explain why passively lit displays (eInk, newspaper) cause less eyestrain. The short answer is eystrain has more to do with contrast relative to ambient light and less to do with resolution.
Tim O
Gee, I thought the iPhone 4 looked pretty spectacular?!? I guess I didn’t do the math. It must be horrible because the numbers say so.
That 720p HD camera is gonna go to waste on such a horrible screen.
Sorry, I’ve had my iPhone for two years now, surfing the web all day every day without eye trouble, until now. I gonna be thinking about eye strain all the the time. Thanks.
Jon H
All I know is I want a 24″ monitor with that dpi.
Martin
@Corpsicle: More importantly, Sprint is admitting that their WiMax 4G network will probably get replaced with LTE down the road. I don’t know if the Evo does LTE, or if Sprint will keep the WiMax around, but I wouldn’t be too certain of my 4G phone still being able to do 4G two years out.
Sprint is in trouble and their 4G rollout is a bit gimmicky – even they admit that.
I have nothing against the Evo – it’s too big and unpolished for my taste, but that’s purely a personal preference, but raving over the whole 4G aspect of it seems pretty sketchy to me.
And the first-hand account that was relayed to me last night is that unless you shove it up against your eyeball, you cannot discern individual pixels. Going with higher resolution won’t necessarily be lost on the user – for situations where you are trying to display a pixel from an image that is slightly offset from the screen pixel, a decision needs to be made on how to do that. There are cool algorithms for that, but in the end if the eye can discern 300 pixels per inch there will be benefits to the user to go all the way up to 600 pixels per inch to handle such situations.
One of the issues in dealing with print screens is how to minimize the interference patterns (moire) that develop which you could not detect looking at the patterns individually but which become very apparent when you combine them. Same applies to displays.
That said, once you hit 300 dpi, you’ve pretty much arrived. The jump to 600 is nice, but hardly necessary. This is in many ways monumental – if Apple can scale this up to larger screens and put out a 3000×2250 display in an iPad (or whatever it works out to) and do the same thing with laptops, then they’ll pretty much win the universe. Dedicated platforms like Kindle can probably keep up with it, but other general purpose platforms like Windows really don’t have that capacity at this time. They can add it, but coordination between the hardware and software makers is key, and that barely exists outside of Apple. It’s a massive competitive advantage if they can expand it beyond the cellphone. As it stands, other phones are in the ballpark of the iPhone 4, so it’s only a minor advantage there now.
robertdsc
The HD video and high res photos are my main draw. I shoot vids on my iPhone 3G through a third-party app but getting HD video in the box to start with is a huge thing for me.
Tim
@Martin: It does strike me as amazing that the new iPhone has a 960×640 screen, and my 15″ laptop is 1440×900. Having a laptop screen of that resolution – or even just the iPad – would be nutso.
Fred Fnord
Umm… this is both confusing and misleading. But on the upside, it’s also wrong.
First of all, the confusing: newsprint is between 300 dpi and 1000 dpi, which is clearly far superior to 326 dpi?
But the misleading part is this: say newspaper print is 1000 dpi. It’s 1000 dpi black and white. Even with text, antialiasing (putting grey around the edges) dramatically increases the effective resolution, to the point where 300 dpi with antialiasing is liable to look better than 600 dpi black and white. If you want a comparison, look at the checkerboard pattern on the following page: http://en.wikipedia.org/wiki/Spatial_anti-aliasing
Those three checkerboard patterns are all at the same resolution. The first is black and white. The other two are antialiased. This is an extreme example, but in this example at least, something like ten times the resolution in the first image would be required for it to look as good as the third image.
(I’m not going to go into subpixel antialiasing, which is required for LCDs for various reasons.)
And then compare the images on the pages of a newspaper with those on the screen of an LCD. Which do you think is clearer? The newspaper image, at any distance less a foot or so, can clearly be seen to be made up of tiny dots. At one foot from my 90-dpi monitor, I can only see the pixels in specific instances (diagonal lines of single pixels, eg, or the intentional single-pixel-dotted vertical lines on this page.)
And that’s not even getting into the low paper quality of a newspaper, and the spread and the artifacts that come from that.
A 300+ dpi screen on an LCD produces a much better image quality in every way than a newspaper. A 150 dpi screen is better in most ways, for most practical purposes.
—fred
CalD
@kralnik:
Agreed. If you want to read a book, get a Kindle (or a book). I think the e-paper devices out there now (Sony Reader, Kindle, Nook, et al) tend to have displays in the 150 DPI range, which with even 16-step grayscale rendering probably gives you the subjective equivalent of text printed on paper at resolutions maybe double that, possibly more.
I keep hearing about the relative reduction in eye-strain for reading with reflected vs. projected light and I’d be really interested to see the research on that. My first guess was that it might have something to do with your eye having to constantly readjust to the spectrum of the light coming off a back-lit LCD screen versus everything else around you, but I’m finding it hard to understand how that would be all that different from reading with a book light…
Anyway, the other advantages of e-paper over an LCD for long doc’s might include the fact that there’s no flicker — a fact I had never really considered that since the flicker of an LCD screen is imperceptible, but I would be willing to believe might be a factor. Also, since the device essentially uses electricity only when turning pages or downloading content, it can run for days and days on an itty-bitty battery and generate almost no heat.
Cons for e-paper would be that it is limited to black and white (for now at least), and is too slow for video. So for short and flashy content such as news or magazine-length articles, where color photos and graphics and/or video are important to the presentation, an LCD-based device probably offers a richer user experience.
Kit
Digital ink is pretty damn good. I have the FoxIt Reader and print is very clear on it.
JBerardi
The first rule of resolution is that you don’t understand it. Look at an iPhone, look at a newspaper, decide which one looks better to you. Do not attempt the math.
CalD
Sigh.
grendelkhan
@Hob: You are correct. The resolution of a bitonal display (e.g., a newspaper, laser printout or offset-print magazine) is not directly comparable to the resolution of a continuous-tone display. Here’s a good illustration. As a rule of thumb, low-resolution continuous-tone displays are better for things like photographs, while high-resolution bitonal displays are better for charts, diagrams and text. (Antialiasing lets you get away with a lot in terms of making text look better, but a high-resolution printout is still invariably superior.)
@cmorenc: Arial is a version (some would say ripoff) of Helvetica, which was not designed for screen use. You may be thinking of Verdana and Georgia, the sans-serif and serif faces designed by Microsoft for onscreen reading. A comparison between Arial and Verdana, at least, shows that the latter is far more readable onscreen, especially at small point sizes.
There’s some conventional wisdom that while serifs provide useful cues at print resolutions, on screens they’re too blocky and end up just being noise. (I think Georgia is more readable than Verdana, but then, I don’t like sans-serif faces for high-volume reading.) On the other hand, Amazon presumably did a ton of research before releasing the Kindle (167 DPI), and they went with a slab-serif font named Caecilia–apparently it’s high-resolution enough for serifs, but not enough for contrasts in stroke weight.