November 7, 2011
I've talked about computer workstation ergonomics before, but one topic I didn't address is lighting. We computer geeks like it dark. Really dark. Ideally, we'd be in a cave. A cave … with an internet connection.
The one thing that we can't abide is direct overhead lighting. Every time the overhead light gets turned on in this room, I feel like a Gremlin shrieking Bright light! Bright light! Oh, how it burns!
But there is a rational basis for preferring a darkened room. The light setup in a lot of common computing environments causes glare on the screen:
If your room's lit, as most are, by fittings hanging from the ceiling, you'll be wanting to set up your monitor so that you don't see reflections of the lights in it. The flat screens on many modern monitors (like the excellent Samsung I review here) help, because they reflect less of the room behind you. And anti-reflective screen coatings are getting better and better too. But lots of office workers still just can't avoid seeing one or more ceiling fluoros reflected in their screen.
A good anti-reflective coating can reduce most such reflections to annoyance level only. But if you can see lights reflected in your screen, you can probably also directly see lights over the top of your monitor. Direct line of sight, or minimally darkened reflected line of sight, to light sources is going to give you glare problems.
Glare happens when there are small things in your field of vision that are much brighter than the general scene. Such small light sources can't be handled well by your irises; your eyes' pupil size is matched to the overall scene illumination, and so small light sources will appear really bright and draw lines on your retinas. The more of them there are, and the brighter they are, the more work your eyes end up doing and the sooner they'll get tired.
While a darkened room is better for viewing most types of computer displays, it has risks of its own. It turns out that sitting in a dark room staring at a super bright white rectangle is … kind of bad for your eyes, too. It doesn't help that most LCDs come from the factory with retina-scorching default brightness levels. To give you an idea of how crazy the defaults truly are, the three monitors I'm using right now have brightness set to 25/100. Ideally, your monitors shouldn't be any brighter than a well-lit book. Be sure to crank that brightness level down to something reasonable.
You don't want total darkness, what you want is some indirect lighting – specifically bias lighting. It helps your eyes compensate and adapt to bright displays.
"[Bias lighting] works because it provides enough ambient light in the viewing area that your pupils don't have to dilate as far. This makes for less eyestrain when a flashbang gets thrown your way or a bolt of lightning streams across the screen," he told Ars. "Because the display is no longer the only object emitting light in the room, colors and black levels appear richer than they would in a totally black environment. Bias lighting is key in maintaining a reference quality picture and reducing eye-strain."
Bias lighting is the happy intersection of indirect lighting and light compensation. It reduces eye strain and produces a better, more comfortable overall computing display experience.
The good news is that it's trivially easy to set up a bias lighting configuration these days due to the proliferation of inexpensive and bright LEDs. You can build yourself a bias light with a clamp and a fluorescent bulb, or with some nifty IKEA LED strips and double-sided foam tape. It really is that simple: just strap some lights to the back of your monitors.
I'm partial to the IKEA Dioder and Ledberg technique myself; I currently have an array of Ledbergs behind my monitors. But if you don't fancy any minor DIY work, you can try the Antec Halo 6 LED Bias Lighting Kit. It also has the benefit of being completely USB powered.
Of course, lighting conditions are a personal preference, and I'd never pitch bias lighting as a magic bullet. But there is science behind it, it's cheap and easy to try, and I wish more people who regularly work in front of a computer knew about bias lighting. If nothing else, I hope this post gets people to turn their LCD monitors down from factory brightness level infinity to something a tad more gentle on the old Mark I Eyeball.
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Posted by Jeff Atwood
Totally agree... on my laptop (MSI CR620, does the job for me!) the brightness in ridiculously bright, and even with it turned all the way down, I still find it too bright :( Gonna have to try out biased lighting!
If you want to get more accurate colors, instead of LED, get a 'fluorescent daylight light'. They are cheap, efficient, last long, and have around 5000k-6500k color temperature.
I disagree... I hate working on my computer in a dark room, it makes the bright screen hurt my eyes. I prefer to work in a brightly lit room.
"like the excellent Samsung I review here" - link please?
James, the linked article is over 10 years old and refers to a Samsung CRT: http://www.dansdata.com/eclipse.htm
I'm a big fan of the IKEA Ledberg and have one stuck to the back of my TV which makes it much more pleasant to look at in the dark :)
I started out using bias lighting when watching movies on my plasma years ago. A bias light with a neutral color temperature around 6500k (for NTSC TVs) really enhances the viewing experience when watching large TVs in an otherwise dark room. I was so pleased with the effect on my plasma that I put lamps behind my monitors as well. Since I just do development on my PC, I wasn't so worried about spending extra on special lamps with the proper color temperature for my pc. If you're a designer, color temp for a bias light is an important consideration since bias light color temp can skew your natural judgement of colors.
If you're looking for a professional grade solution to the problem or looking for more info, checkout http://www.cinemaquestinc.com/ideal_lume.htm. I bought a plasma bias light from them many years ago and have been very happy with it.
Right now I'm reading this on my phone lying in bed. The screen imo is way too bright, despite that I turned the brightness down to 0%. (No I don't know how that works either.)
You know, I had always wondered why I liked my lamp placement so much (pointed directly behind my monitor).
I'm afraid I have to agree with Tomlev2. My 50-year-old eyes aren't what they used to be, and in order to see well I need lots of light. As for reflection, the only place I get any reflection is the bezel of my monitor, the screen doesn't reflect the room behind me.
What make me alternatingly laugh and scream is the excuse many of my co-workers use, which is, "I don't like the 60hz refresh rate of the flourescents." Oh, you mean the EXACT SAME REFRESH RATE YOUR FLAT PANEL MONITOR USES? I personally also consider it just a tad unprofessional. I don't know about you, but if I walked into the office of my doctor, lawyer, accountant, financial planner, or any other profession and the office was all dark except for the glow of the monitor I'd find another person to handle my business.
Our company uses slotted metal diffusers fitted on every fluorescent fixture in our work areas, that direct the light mostly straight-downward. The result is zero reflections on our LCD screens, and plenty of lighting.
"What make me alternatingly laugh and scream is the excuse many of my co-workers use, which is, "I don't like the 60hz refresh rate of the flourescents." Oh, you mean the EXACT SAME REFRESH RATE YOUR FLAT PANEL MONITOR USES?"
Erm. What refresh rate? Are you using CRTs?
In any case, the fluorescent flicker is hardly an issue. It might be an issue with some cheaper and older tubes (like the sort you might find at stores), but I have never, ever seen a compact fluorescent flicker. I can't stand CRTs at 60hz btw, because I can see the flicker very clearly.
I'm with Tomlev2 and Craig Warner. This article is way overgeneralized.
*Many* computer geeks like it dark. *Many* computer geeks like it bright. My experience has been that the split is roughly 50/50 -- from working at a place with private offices, where people could control their own lighting.
And of course, there are all the people who have medical reasons to like bright light. People like Craig, who are above the median age in the industry. People who are low myopes or mild presbyopes -- brighter lighting may increase the depth of field just enough that they don't have to wear glasses to see the screen. People like me, who need bright lighting so that the pupil does not dilate past the blend-zone on our corneas -- this includes people who've had refractive surgery, and people who wear hard contact lenses (which are smaller than soft contacts).
@Craig Warner and Stephen Eilert: Modern fluorescents are electronically-ballasted, so they do not cycle at the line frequency (60 Hz or 50 Hz) -- but at 20-30 KHz. The "refresh" rate on LCD monitors refers to how fast the image data changes -- not to how fast the backlight cycles.
@tomlev The screen being too bright is the source of your problems, did you read the article? ;). @craig Refresh rate isnt very important with LCDs because they have long decay rate, therefore no flicker.
Personally I use xmas (or the white version) lights around my workspace, it provides for warm diffuse light.
An interesting side effect of having lower levels of light is that the LEDs that indicate (e.g.) that the monitor is turned on become proportionally much brighter. The blue LED on the front of my monitor becomes a super-bright point light source, and I've had to cover it with a yellow stick note.
Couple of other notes ... there might be a difference for those who wear glasses, which can enhance glare. (Especially if they're micro-scratched.) And per Craig's note, older eyes have their own set of issues. Anyone who has early-stage cataracts (i.e., if you're in your late 50s or beyond) will likewise experience various diffusion effects that make it harder to deal with high-contrast light sources -- which is one reason why night driving becomes so much harder.
It's definitely worth experimenting with different levels of ambient light, different brightness levels on the monitor, etc.
This article seems to assume that people are working with the terrible black-on-white colour scheme. As someone who prefers yellow-on-black for purposes of minimizing fatigue, should I avoid bias lights? After all, I've adapted my setup so that a completely dark room is entirely comfortable and the negative space is not blindingly bright in comparison to my surroundings.
I don't know why so many of you like being in a dark room. It is proven to increase headaches when looking at a bright screen, and I find headaches to be a distraction.
I like this idea very much. My question is how do you get the other people in your office to respect the lighting? I literally crawl out of my skin when the overhead lights come on.
I work under a 16-foot ceiling (the alternative being not-quite-8-foot ceiling and much less real estate in the X and Y axes). It's a kind of fluorescent retirement home, that is, that's where they come to die (and take your eyes along with the process).
I don't think back-lighting would help me at this point. But thanks, I'll consider it for home.
Adafruit has a pretty cool back lighting implementation. They demo it with HD movies but I wouldn't think it would be much different than PC monitors.
The thing I find challenging, is lighting a paper notebook (or other reading material) that sits beside the keyboard, without causing glare on the screen.
@Jonathan Hendry, I have my lamps carefully positioned just behind the plane of the monitor. E.g. at home, a light placed on a shelf above neatly lights the whole surface below without shining on the front of the screen.
One thing that you have to be aware of when changing your monitor's setting from "project an X-ray of your skull bones onto the wall behind you" to something more reasonable is that many monitors that use flouro backlights have inverters that only work properly above 95% load. Once you get below that (meaning you reduce the brightness below 95% or so), they start to whine very audibly. Generally you won't hear this because the PC they're attached to produces enough noise to drown them out (although you may get slight headaches or feel somewhat nauseous from the high-frequency whine), but with a quiet PC it can become very obvious. I've had several Samsung's that whine unbearably when dimmed, and had to send two Acers back before they sent me one that's mostly silent.
Unfortunately there's no easy way to tell whether a monitor will do this (presumably never LED ones don't have this problem unless there are PWMs that oscillate audibly as well), so if you're worried about this then make sure you're buying from a place with a liberal returns policy.
It gets more complicated when photography is your hobby - the colour of ambient lighting affects your perception of colour on the screen. In Australasia the flicker of ambient light is 10Hz removed from that of the monitor, which is very painful. And it is all too common for LCD/TFT screens to flicker at lower brightness settings.
On the subject of room reflection, anti-glare coatings have a problem in that that they significantly reduce screen contrast - best results for photography come from high-gloss screen finishes (which are an option with some high-end brands), but then you have to rearrange the room to avoid reflections.
If the CRT screen is too bright and the room is dark, I get burning red eyes after a few hours. The remedy is to lower the contrast.
LCD is much better for your eyes than CRT, in that regard.
How do you reckon I could do this in an open cubicle in a bank?
The CRT is just burning my retinas away. I tried dimming the brightness of the 20 year old screen to no avail it is still torture. At home I already tried bias lightning almost by accident (my lights are so bright, that they reflected off the screen so I moved them behind and it has proved to be quite the nice solution.
Still people that works on corporate too light with high windows places with old as fossils CRTs are doomed to not be able to see forever.
One more recommendation for the bias lighting in the home theater. I bought the http://www.cinemaquestinc.com/ideal_lume.htm a few years back when I had a big screen CRT Sony, and I still love it on my 46" LCD Sharp.
I had the Eclipse computer light years back and loved it. Sadly it was broken during a move. I ended up replacing it with a small halogen desk lamp from Ikea sitting on a shelf above the monitor. I hadn't thought about doing something like the ideal-lume, but it's a good idea.
For those complaining about how sitting in a dark room hurts your eyes... THE PURPOSE OF THE BIAS LIGHTING IS TO PREVENT THAT. Read the content over at Cinema Quest about bias lighting for TV's and why and how it works.
I hate you guys, as a front-end developer designing stuff most of the time I can't work with brightness lower than 75/100 (while my LCD's brightness is 300 cd/m2).
In addition this 15$ LEDBERG costs over 30$ in Europe, which is totally unfair with an average salary of 650$ in my country. Wow, in fact this 30$ ledberg is 20 cms shorter.
Now I'm MAD :D
But really - I've been waiting for this bias lightning post for a long time and after all these years ;) I found it too short! :)
I didn't notice any particularly bright LCD's until a couple of years ago. I don't know if that is just the evolution of the technology or that I am buying higher up the range than I used to when I was a poor student.
My Apple Cinema display on full brightness actually hurts my eyes until I adjust to it. Obviously I don't keep it at that level, my HP envy laptop is much the same. They boast about the screens but full brightness is ridiculous.
Thanks for the interesting article and the links. For years I have been lighting my computer work area with a swing-arm, Luxo-style desk lamp with a simple 60W incandescent bulb. I point the lamp upward to the white ceiling and the direct illumination washes the wall as well. Now I know what to call it!
I recently moved the HTPC with its 50-inch screen to a room whose walls are painted a very dark green. The indirect lighting does not work nearly as well. Any commenters who have ideas, I would love to hear them. (Or maybe there is a Stack Exchange site for indirect lighting now?)
Is this based on science? All ergonomics manuals I've read suggest proper overhead lighting is preferable to a darkened room (albeit with back lighting).
I've also asked this on Skeptics.SE:
Is it preferable to use a computer in a darkened room?
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I didn't know what bias lighting was before reading your article, thank you very much for sharing this. Today I went to IKEA and saw those DIODER led lights and went on buying them to give a try. I must say it really does the difference and makes my home programming a lot comfortable to my eyes. Here is my picture of my (yet unfinished) set:
Thank you very much Jeff!
On related note doesn't geek worry about there eye little bit ? while they continuous work on there laptop , desktop and Ipad doesn't there eyes saying them dude please take a break.
I have an Ambilight TV from Philips that has those LED strips at the back that automatically adapt to the colors on the screen - I swear I'm never going to buy a TV without it anymore. They should make computer displays with Ambilight too.
I'd definitely recommend http://stereopsis.com/flux/ before anything else. Also, any light behind your screen will bleed through, which is less than optimal and will strain your eyes.
It is like someone saying "You're now that you are blinking". Now that I've had the Dioder lights in I've noticed the difference. Of course they also make good mood lighting for playing BF3.
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The thing I find challenging, is lighting a paper notebook (or other reading material) that sits beside the keyboard, without causing glare on the screen.
The same situation happened on my tablet.
I'm using http://stereopsis.com/flux/ right now as well as a lamp behind my monitor and I still think it's too bright. I think the problem is most websites. Everyone has different preferences so I'm not saying it should be one way or the other, but we *should* have the option to select a dark theme on a web site and vice versa. I wish Google+ had this feature, because it's way too flippin' bright for me.
it's good for keeping lightning mode good than pre built, i will set my bis lightning as per mentioned in the post and it's good for those who seat maximum time in front of PC.
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1. deeply unhappy about being obliged to provide credentials for another application in order to be able to comment here.
2. bought the Antec lighting kit for its usb connectivity and wish I hadn't. it's not bright enough for anything and it doesn't switch off when the machine switches off == much fumbling around in the dark to dis/connect. as others have said f.lux is a much better solution.
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