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What Font Color Is Best For Eyes?
juraj writes "What font color and what background is best for the eyes, when you work for a long time? I have found various contradictory recommendations and I wonder if you know about any medical studies on this topic."
Yellow on red seems like a very popular high contrast color combination for several years.
Serious? Seriousness is well above my pay grade.
Background :#FFFFFF
Text: #FFFF00
You are now manually breathing.
I've been saying this for years, but no-one's paying attention, apparently...
When you work with computers for long periods of time, the colour of the font is nothing compared with taking regular breaks. Look out the window. Go for a walk. Make some tea. Bump up the font size. Get a bigger monitor and put it further away.
You are focusing on a tiny, tiny, tiny piece of the problem. There are almost certainly a ton of ways in which you could reduce eyestrain by gigantic amounts in comparison without bothering with something as trivial as font colour.
Like my porn, it's black on white.
Let's face it, most of us are scoffers. But moments before zero hour, it does not pay to take chances.
... then shake the monitor.
The human eye is naturally lazy, and likes to look at things that do not cause it to send strong signals. To that end, a black background is essential for "easy on the eyes" formatting. From there, pretty much any light colour can be use for the text.
When I was in uni, I used to buy special black paper "visual arts diaries" and write my class notes using a gold, silver, bronze, or plain white ink pen. This had the effect of making my pretty poor handwriting easier to read for most people, and also reducing the effects of my dyslexia; I would make less errors like inverting a series of numbers as I wrote them down and the like.
I'll chime in as a physician.
:p
I always wondered in medical school what causes eyestrain -- your mom probably told you "don't read in poor light," but since the photons are easily sufficient to give an image on your retina, this didn't make sense to me.
It turns out that your eye muscles have a difficult time obtaining a rapid and precise focus with poor light, which gives less contrasts on the edges that are detected for sharp focus. In low light conditions, the eye muscles are rapidly focusing back and forth, and these micro-contractions can fatigue them similar to the other large muscles of your body. As an analogy, imagine walking on level ground versus on a balance beam. You are constantly contracting different adjustment muscles to walk on a balance beam, using more energy and promoting fatigue.
So, in answer to your question, you would want a high-contrast color scheme to make it easy for your eyes to focus on the letters. "Duh," I hear you say.
Next, I would recommend minimizing the difference in brightness between your monitor and the outside environment and its background. That is, in a dark office have a dark monitor, and in a bright office, a bright one. Why? Well, same reason -- your eye muscles have to dilate your pupil every time you look away from a bright monitor to a dark monitor. More contractions / adjustments -> more fatigue. Not only that, but the high brightness contrast will give ineffective normalization of light across the eye receptors and could cause headache.
Regarding your study question -- difficult to fund, and difficult to accomplish. I guess you would have to divide several hundred office workers, and try to have them work the same hours under same conditions with different fonts, and then ask a subjective question regarding symptoms. It could be done, but I am not sure of any well-performed efforts that have addressed this question.
In summary, I would just choose contrasting colors that you like or find subjectively pleasing, and then keep the brightness on your monitor appropriate for ambient lighting. Also, don't forget to focus on the numerous other ergonomic factors on your workstation. I see a *lot* of people with bad backs from the workplace, but there are a lot of 80 year old secretaries that are not blind.
Cue the contempt for expertise from the anti-intellectual crowd now.
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Just look on myspace, then do the exact oppersite.
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Gray is a color, grey is a colour.
Your screen is dark. your text is likely to be eaten by a grue.
The CB App. What's your 20?
You are on the right track but there is more. Yes, higher contrast is better than lower contrast. But how this works with color is complicated.
One big issue is that the eye is not perfect optically. It cannot focus all colors at the same focal plane. Just how well it does varies by individual and the optical conditions of their eyes, and the quality of corrective lenses (which usually make it worse with respect to the ability to simultaneously focus all colors).
An important factor to consider here is which color or colors the difference is at the edge being focused on. For example in the "hot dog" pattern that has been mentioned in a reply here, the difference is actually in green. If the red level of the yellow part is exactly the same as the level of the pure red part, then all the difference is in green and this is an issue of green contrast. Yellow on red like this is essentially the same as green on black ... except that the extra red light with yellow on red causes the iris to close down more than the darker green on black would.
I find blue to be the worst to focus with. That may be because my sources of blue light are not sufficiently narrow band in the spectrum. Being spread out over the spectrum, it basically comes in fuzzy. Blue is also lower in contrast.
Green (be it green on black or yellow on red or even cyan on blue) is better.
Red seems to be the best in terms of focusing a sharp defining edge. You get red contrast with red on black or yellow on green or magenta on blue.
Unfortunately, effective contrast goes down when extra light is added in other colors. So you have to find a balance trading off the sharpness of the edge vs. the contrast. I've found a good compromise in orange on dark green (the level of green in the orange is the same value as the green background). Think of the orange in a neon sign on the green felt of a pool table. Then when I need to highlight something, I shift over to pink on cyan ... basically add the same level of some blue to both the orange and the dark green.
A related issue is light quality when reading a book or newspaper. Usually we are stuck with black letters on white paper. The consideration is then what type of light. I find that incandescent light, or sunlight, works nearly best for me for long term reading. Fluorescent lighting is worse. Ironically, I find high pressure sodium vapor light is about as good as, and sometimes somewhat better than, incandescent light.
To understand this, look at the spectrum. Incandescent light has a fairly even level through all light wavelengths. This makes those black on white edges a bit fuzzy. But fluorescent light has two narrowband peaks at a red and green wavelength (the blue is broader). This can make the text edge sharper ... twice. The eye ends up with two contrast edges. I believe this increases the eyestrain by causing the focus to be constantly jumping in and out to alternate the focus on the two different edges. It's a very small adjustment, but it is there at least for me. With incandescent light, it just settles in the middle of the fuzzy range and doesn't change much. And this is affected by how much light there is, which dictates how small the iris becomes. Higher light levels with a smaller iris won't change the effect from fluorescent as much as for incandescent, since with fluorescent the two contrast edges are already rather sharp due to the two narrowband spectral peaks. But for incandescent, the high light level helps (up to the point that intensity is too stressful).
This is why I believe we still need to keep some incandescent lighting around for reading and other close/fine work for long periods of time. I get a headache when working on things I need to look at closely when doing so under fluorescent light. The onset is about 25 to 45 minutes. I don't get the headaches under incandescent. And I have verified that the flicker is not the cause. White LEDs
now we need to go OSS in diesel cars
While you joke about red on yellow, I personally use a three color font system that is brown stokes infilled with a pale orange sitting on a white background. It's very legible as you can see in this example here
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If you read the follow up you'll see that that is not a feature of Leopard, but the result of sub-pixel rendering. It's a technique for making text look better on LCDs.
Steve Gibson has an interesting article on it here:
http://www.grc.com/ct/ctwhat.htm
Women are like electronics: you don't know how damaged they are until you try to turn them on.
CRT pixels do not line up precisely with their r, g, and b light emission points, at least on most CRTs. If you look at a single white pixel on a field of black through a lupe, you'll see it's composed of a number of red, green, and blue dots, not one dot for each color. Look at a different pixel, and the exact pattern will be different (shifted a little).
They use a couple of electromagnetic coils in the rear of the tube to guide an electron beam to the right point on the CRT's surface, but it is not so precise on most models (though maybe some really high end stuff for scientific work) as to be able to exactly hit specific phosphorescent spots.
This is why sub-pixel rendering works on LCDs but not CRTs (which turn on and off [or shade] specific color points digitally), because we know the exact shape and color layout of each pixel.
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