Can you imagine how difficult it is to read a ridiculously long writeup that consists of a single paragraph, in 9-point Arial? My face is two feet from the screen and after a couple lines, I find my eyes drifting up or down to another line, missing something or getting a weird sense of deja vu. How am I gonna know if your writeup is any good if I can't finish it? Big-ass font land1 is no option because I'll start looking for gremlins popping out of the holes in the "O"'s. After a while my head begins to throb. Come on folks, How hard is it to stick a few <br> tags2 in there? They're only 4 extra characters each, and we're not your English Composition Professors, we're not gonna flunk you for too many paragraphs! Of course, the longer a paragraph is, the more I can count on people skipping stuff. When in the Course of human Events, it becomes necessary for one People to dissolve the Political Bands which have connected them with another, and to assume among the Powers of the Earth, the separate and equal Station to which the Laws of Nature and of Nature's God entitle them, a decent Respect to the Opinions of Mankind requires that they should declare the causes which impel them to the Separation. We hold these Truths to be self-evident, that all Men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty, and the Pursuit of Happiness. I appreciate being able to establish the meaning of what I'm reading to determine if I agree with it, disagree with it or think it's trash.
1"Big-ass font land" copyright 1998, Chaosmonkey
2<br> tags are now a Bad Thing. Use <p> - </p> pairs instead (These are only 9 extra characters each).

The difference between a book and a monitor is that when you are reading on a screen, your eyes can't scan smoothly and accurately (and quickly) back to the beginning of the line of text you've just read, so that you can read the next line. Your eyes could manage that feat easily if you were reading a book, because the book is always there, but it's not so simple when you're reading on a screen. The reason for this is that when you are looking at a screen you are looking at the equivalent of a movie made up of flashing still images that interrupt much longer periods when there's no image at all. None. As I'll detial later, this is not just of cathode ray tubes, but its of devices using alternating current generally. Don't be to sure your LCD screen is better.

Swing your eyes very rapidly back and forth from one side of a movie screen while your're watching a flick and you'll notice that it breaks up into separate and confusingly overlapped images. (So we learn not to do that, and get a bit of a glassy stare at the movies or in front of the tube.) Same with a computer screen. You can't easily follow a line of text backwards on a computer screen at a good speed because it literally isn't there most of the time that your eyes are moving - your brain gets two or three disjointed images as your eyes try to swing back to the start of the next line, at most. Trying to slowly and carefully follow these disjointed images so precisely as to get to exactly the next line without any external clues (such as a paragraph ending) to help you, really can give you a headache.

If so, your headache comes in part from straining the eye muscles to hold the eyeball extremely steady (literally.) It always takes a lot more individual muscles to move precisely than to move easily and sweepingly, and some of those muscles will have to be tensed in opposition to others. Since many of these muscles are rarely used otherwise they may complain or it may require a lot of mental effort to control them. Then again, you may just find the extra time it takes to your place at the beginning of each new line annoying.

So that's where paragraph breaks come in. On the net, we use them (albeit unconsciously for the most part) to reorient ourselves and find the next line as we read. But if what we are reading is a long sentence in the middle of a screen long paragraph, just try to read quickly and you're lost. Repeatedly. Even trying to stay on exactly the same line may be difficult. This is because you can't count down from the paragraph's start, or up from its end. The ends of the paragraph are outside your fovea's range, so you'd have to shift your eyes, losing the line you were on, anyway.

There was a time when publishing was in it's infancy, and fewer people were literate when the problem of keeping one's place was taken much more seriously. We've all heard the word "catchword" but may not know where it comes from. In earlier days, in order to help readers keep their place between pages, a "catchword", namely the first word of text on the following page, was printed in the lower right-hand corner of every page of a book. (Then again. there was a time when the Greeks didn't use spaces between words to help readers out a little.) Since monitors have made reading a bit more difficult, it's helpful to aid the reader a bit more again in keeping their place.

The most conservative rule of thumb is probably to make sure that every line of text is within four lines of the start or end of a paragraph - which means that more than eight lines for a paragraph may actually be too many, and sixteen are - on a computer. The degree to which you can move your central vision processing power (or focus of attention) away from the point where your fovea is actually looking, may change this, making larger paragraphs quite readable. However, most people don't even know this can be done, and won't find it an easy skill to pick up, particularly if they aren't frequent lucid dreamers. It's probably kindest to be conservative, therefore, and write for those who haven't developed any siddhis, or aren't wholly comfortable reading ofv monitors.

Admittedly LCD screens are a bit better than cathode ray tubes in regard to display persistence, but only modestly so. Because greater image persistence would cause "smearing" of the pointer, or of objects moving in a game, manufacturers generally opt for higher refresh rates and also the lowest possible image persistence - which is actually bad for reading. Maybe someday, on non-cathode-ray-tube screens, you'll be able to adjust image persistence so that it's more like a book when you're reading. Maybe they'll make the screens smarter so that they adjust themselves, and provide near-continuous image persistence when the image is static in any case, or when the screen contents show that you're just reading (anybody got money for a patent?) Until then, break up the paragraphs, baby. Eight to sixteen lines at most, most of the time.

That or we could all snap up those ancient monitors with cheap green phosphors on which you could watch the letters sloowwwlllyy fade away after you unplugged them.

Don't be too sure your wonderful LCD screen doesn't flicker at all: remember that alternating current is off and on. It's true that many devices "correct" AC current by transforming ot into direct current - but this almost always alters only the direction of the current, not the fact that that current is intermittent. Devices that remove the intermittency exist but are much rarer. But in any case, we don't all have fancy LCD screens yet. If nothing else, have mercy on those of us too poor to upgrade yet.

I should mention that there are other solutions to this problem that are used elsewhere on the net: one common one is to revert to a "broadsheet" style of presentation using very narrow columns. This makes the job of scanning back to the beginning of the next line much easier, which is why is was popular to begin with in much less literate times; it wasn't just a fashion statement then, and it isn't on the web, now.

Another method is to make every fourth or fifth line of text a distinctly different color, or to slightly bold it to get a similar effect, providing the equivalent of graph paper for text readers, or go down a line and a half instead of just one line. But this hasn't caught on everywhere yet and might make you feel too much like a four-year-old. It would be pleasant if your OS or browser offered this periodic bolding or coloring as an option you could toggle on if desired. Then again, as the Russians say, "If my Grandmother was an omnibus, I'd ride into town for free."

I admit, this new tradition of shorter paragraphs somewhat undermines the old semantic purpose of dividing text into sections of uniform meaning. But until the headaches flickering decreases, we'll all just have to live with that. Perhaps you could bold the first three words of every bigtime semantic paragraph break, if you want to demonstrate visually that your writing is even more coherent than it appears, or use an html break to create subparagraphs that don't represent semantic breaks, if you really hate the idea of very frequent paragraph breaks.

In summary, sometimes technology adapts to us, sometimes we have to adapt to technology. For now, we're in one of the latter times.

Written for my sins. (in an earlier version of "Little Bubble Worlds" especially.)

First posted Jan 30 2004 or earlier

Last revised July 9, 2004

Thousand word paragraphs look bad no matter what medium they're displayed in. In a normally-printed paperback, a thousand word paragraph would be a page and a half long. 1000 words in ten point font take up a whole side of A4 paper. Imagine how bad a ten paragraph dissertation would look!

The main difference between a screen and a book is that a column in a book is four inches (and ~12 words) wide, while a column on a screen is 12 inches (and ~25 words) wide. This is a much larger distance for the eye to travel, and people who are not used to reading off a screen can have difficulty with it. To be really technical, when reading a book, most of the line is seen by the fovea at any given time, whereas when reading a screen less than a fifth of it is. Scanning back to the start of the line is much more difficult, as to the eye , most of the text is an indistinguishable blur.

There are easy workarounds though - most browsers allow you to select text, and show your selection in a different colour. This highlighted text gives the eye a reference point, distinguishable even though it is not in the fovea. The highlight need not even be on the current line; the eye can seek quite well to the start of lines within an inch or two of change in colour. It's only with large blocks of the same colour text that it has difficulties.

This is why normal paragraphs are easy to read on a screen; the eye can use the gaps between paragraphs as landmarks.


It has been suggested that long paragraphs on computer screens are difficult to read because of the flicker. This is incorrect, however, as the same paragraph is as difficult to read on a CRT screen (which does flicker) as on an LCD screen which does not. It has also been suggested that LCD screens merely flicker less than CRT screens. This is also incorrect, as because of their completely different technology, LCD screens do not flicker at all.

Phosphor-based screens (CRTs, Plasma screens, CRT projection screens) flicker, because the image is produced by small dots of phosphor1, which produces light when it is excited by high-energy electrons. When the phosphor is not being excited, the light output steadily drops. Rather than excite each phosphor all the time (which would require an enormous amount of electronics), the phosphors are excited in sequence by a single electron source2. While the electron source works on other phosphors, the phosphor discharges its stored energy. Depending on the formulation of the phosphor this may take a long (providing a bright, low-resolution, high-contrast image that deals poorly with motion), or short time (providing a dim, high-resolution, low-contrast image that deals well with motion). Televisions, and text-mode monitors use the former, modern monitors use the latter. LCD screens behave completely differently.

An active matrix LCD screen is an array of subpixels, each of which produces no light itself. Each subpixel is made up of a tiny memory cell, a dot of liquid crystal, and a coloured filter (to make it red, green, or blue). The subpixels are illuminated from behind (usually by a cold cathode lamp), and (depending on the state of their memory cell) allow some, all, or none of the light through. Because the liquid crystal is constantly powered by its memory cell, it does not flicker, and does not need to be refreshed.

The 'refresh rate' of an AMLCD is the rate at which visual information is written to the memory cells of the active matrix: while the liquid crystal can stay at a constant transparency indefinitely, there is an upper limit to how fast it can change this transparency. More expensive screens can change colour, and therefore refresh, faster than cheap screens.

Older 'passive matrix' screens do flicker, because their liquid crystal cells are driven by capacitors, charged by pulses which scan across the screen. Aside from flickering, these obsolete screens had enormous problems displaying moving objects (such as the mouse pointer), and are virtually impossible to get hold of nowadays. Every computer, laptop, mobile phone, and handheld console3 produced in the last five years has an active matrix screen.


1 - Not phosphorus, though most phosphor formulations contain a lot of phosphorus.
2 - To be really pedantic, plasma screens have one electron source per phosphor, but these are powered by a much smaller number of energy sources, which scan across the screen in much the same way as a CRT's electron beam, or a passive matrix's transistor pulse.
3 - Compare the horrible blurry gameboy and gamegear with the newer active-matrix gameboy colour and gameboy advance

I cite:
'LCD monitors - Of Pixels and Pitches' : http://www.computerwriter.com/archives/1998/cw092498.htm
'Thin-film Transistor LCD Displays' : http://www.cs.ndsu.nodak.edu/~revie/amlcd/

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