My simple hack for increased alertness and improved cognitive functioning: very bright light

This is a simple idea that I came up with by myself. I was looking for a means to enter high functioning lots-of-beta-waves modes without the use of chemical stimulants. What I found was that very bright light works really, really well.

I got the brightest light bulbs I could get cheaply. 105 watts of incandescents with halogen gas, billed as the equivalent of 130 watts of incandescent light. And I got an adaptor like this that lets me screw four of those into the same socket in the ceiling. The result is about as painful to look at as the sun. It makes my (small) room brighter than a clear summer's day at my latitude and slightly brighter than a supermarket.

I guess it affects adenosine much like caffeine does because that's what it feels like. Yet unlike caffeine, it can be rapidly turned on and off, literally with the flip of a switch.

For waking up in the morning, I find bright light more effective than a 200mg caffeine tablet, although my caffeine tolerance is moderate for a scientist.

I have not compared the effects of very bright light to modafinil, which requires a prescription in my country.

When under this amount of light, I need to remind myself to go to bed, because I tire about three hours later than with common luminosity. Yet once I switch it off, I can usually sleep within a few minutes, as (I'm guessing) a flood of unblocked adenosine suddenly overwhelms me. I used to have those unproductive late hours where I was too awake to sleep but too tired to be smart. I don't have those anymore.

You've probably heard of light therapy, which uses light to help manage seasonal affective disorder. I don't have that issue, but I definitely notice that the light does improve my mood. (Maybe that's simply because I like to function well.) I'm pretty sure the expensive "light therapy bulbs" you can get are scams, because the color of the light doesn't actually make a difference. The amount of light does.

One nice side benefit is that it keeps me awake while meditating, so I don't need the upright posture that usually does that job. Without the need for an upright posture, I can go beyond two hours straight, which helps enter more profoundly altered states.

After about 10 months of almost daily use of this lighting, I have not noticed any decrease in effectiveness. I do notice I find normally-lit rooms comparatively gloomy, and have an increasingly hard time understanding why people tolerate that. Supermarkets and offices are brightly lit to make the rats move faster - why don't we do that at our homes and while we're at it, amp it up even further? After all, our brains were made for the African savanna, which during the day is a lot brighter than most apartments today.

Since everyone can try this for a few bucks, I hope some of you will. If you do, please provide feedback on whether it works as well for you as it does for me. Any questions?

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After about 10 months of almost daily use of this lighting, I have not noticed any decrease in effectiveness.

Thank you for waiting to see whether this works in the long term before posting.

No, I'm pretty sure I would have been interested in this earlier...

If you do, please provide feedback on whether it works as well for you as it does for me. Any questions?

Why not do a self-experiment? It's not like turning on lights is hard to randomize.

What's the point of randomization if you can easily tell the difference between a bright bulb and a dim one?

Of course you can tell the difference. That just means that your self-experiment is not blinded (if you'll pardon the pun).

Randomization still eliminates some confounding factors even without blinding. For example, you might be more likely to decide to turn on your bright lights when you're already feeling alert.

Yep yep. It's just not quite as strong as a blind study, but that's fine for these purposes.

I've seen the light as well. Fiat lux!

Also like your argumentum ad savannam africanus. That should be a thing. Recreating the desert's albedo.

argumentum ad savannam africanus

argumentum ad savannam africanus

That's awesome.

Fiat lux!

argumentum ad savannam africanus

You must be a latin scholar.

Haven't even taken latin at school, picked up some later when I fell in with the wrong kraut, and again more with some [p]re-med-ial courses. Overcompensating!

Well, shouldn't it be "argumentum ad savannam africanam", if the adjective refers to the savanna (which is feminine singular accusative), or eventually "africanum", if it binds to the argumentum (which is neuter singular nominative)?

I can't be the only one thinking "people called Romanes, they go the house?"

Well, I thought Kawoomba knew it better than me, and it would be a u-declination (africanus, -u). But no, according to the English Wictionary entry on africanus, it is a/o. So, africanam. Though the last time when I was learning latin was eight years ago, so...

(edit) When we are at it, what's it in Lojban?

I am not a Latin specialist, so I have to rely on Wikipedia in this, but it seems that u-declension is a category for nouns, not adjectives, which seem to never have -u- in feminine accusative singular ending; also, even a u-noun would have -um, not -us, in singular accusative.

I have no idea about Lojban.

It's the ((African savanna) argument), an argument from the African savanna; not the (African (savanna argument)), an African argument about savannas.

I supposed so, but wanted to cover even the less probable alternative in a single comment. (Which purpose is now defeated by the need to write this second comment.)

First time commenting here. A friend linked this thread on Facebook, and have something to add about the possible mechanisms of light therapy.

So far as I am aware, the mood and concentration enhancing effects of light therapy work primarily on the Serotonin -> Melatonin synthesis that occurs in our brains.

Basically, when it gets dark and gloomy, our brains start manufacturing melatonin, to make us feel tired and sleepy. In animals such as bears, the winter induced melatonin is a signal that it is time to hibernate.

The interesting part is that the chemical from which melatonin is synthesized is serotonin, which as we know is involved in mood, appetite, sleep and all sorts of human behaviour, and is the primary neurotransmitter system targeted by SSRI antidepressants.

Hence less light causes more serotonin to turn into melatonin, which makes us feel both tired and potentially moody. Therefore its reasonable to hypothesize that light therapy works by reducing the rate of melatonin synthesis and maintaining higher levels of serotonin.

I have never heard of light therapy affecting adenosine levels in the brain. This doesn't mean that it doesn't, just that I am unaware of evidence that this is the case. A quick pubmed search didn't reveal any papers to back up this hypothesis either.

In my personal mood and productivity experimentation, I have found that supplementing my diet with 5-hydroxy-tryptophan (5HTP) in addition to using a high lux lamp does wonders for my mood and productivity (sorry I cannot quantify "wonders").

Basically, the synthesis path normally goes: Proteins -> Amino Acids (including tryptophan) -> 5-hydroxy-tryptophan (which is capable of crossing the blood brain barrier, and does so but in competition with other amino acids) -> Serotonin (5HT) -> Melatonin (when dark or in low light, technically a lack of light hitting the retina).

So, potentially supplementing with 5HTP or another source of tryptophan in addition to light therapy should be more effective at enhancing mood/productivity by both increasing the rate of serotonin synthesis and decreasing the rate of serotonin metabolism. Assuming serotonin is responsible for these effects, of course.

I have read that typtophan supplementation is much better than 5HTP as 5HTP mostly winds up in the liver. OTOH, Ray Peat claims we're getting abnormally high amounts of tryptophan in our diets from over consumption of muscle meats anyways.

Anja and I just went out and bought three 120W lights (for construction sites; we had trouble getting good bulbs).

Here at the Singularity Institute, we take ideas seriously.

We bought three of these.

We've tried to put them around the room evenly. You can see all three in the right picture (one in the foreground). We'll report back in a few weeks about how much it helped.

We'll report back in a few weeks about how much it helped.

How are you measuring how much it hurts/helps?

Completely non-rigorously. I'll probably just look at my hours, and reflect on how I feel about its effect.

I'm curious how this worked for you. (The lighting, not particularly the experimental method.)

Unfortunately not enough of an effect for me to claim anything. I do like it brighter though, so I will continue using the lights.

It looks as though you'll soon be needing some diffusers...

The nice thing about CFLs is that you can put really quite bright ones in small desk lamp housings - because they dissipate a lot less heat. Only problem is physical size of the bulb.

Well, that sucks, since CFLs are only going to increase. There's a pile of crank sites about CFLs and migraines; closest to non-crank I can find quickly is this Australian government site, which says this from CFLs (as opposed to the older ones that flicker at 50/60Hz) is generally badly set-up lighting.

Your "poorly set-up lighting" is a reference to this:

the primary cause is likely to be glare, highly contrasting, or inappropriate light levels. These problems are a result of poor lighting design rather than a feature of fluorescent lamps and can occur with any lighting technology if used inappropriately. Light fittings that enclose lamps and distribute light evenly without compromising light output and efficiency can help avoid these problems.

Poor set-up is unlikely to be the cause in my case because I did not make any changes except to replace an incandescent bulb (on my desk) that never gave me any problems with a CFL of similar brightness.

I do not dislike all fluorescents. For example, the cold-cathode fluorescent lamps in my monitor and my best friend's TV give off completely-unproblematic very nice light. (The light from the two LED-backlit devices in my life on the other hand is not nearly as nice.)

haha You beat me to buying, but I beat you to installing.

Ok, now I'm living lumenously, too. I definitely feel an immediate difference, but the long-term utility and whether or not my ceiling catches on fire remains to be seen.

I also have been using bright lights to help stay alert. This has helped a lot getting used to polyphasic sleep. (It also helps to use a sleep mask. Bright light while awake, no light while sleeping.) Since I started, I have noticed that I have less need for this effect, but it is still nice.

I had looked into the light therapy bulbs, but the price made me think I should at least try the brighter conventional bulbs first, and this turned out to work fine.

My personal subjective experience is also that I find very bright artificial light after dark improves my mood, alertness and cognitive ability.

However, the personal subjective experience isn't universal: many people I've shared home or work spaces with have complained when I've installed bright lighting. They've found it too bright, or too clinical, or too much glare, or gives them a headache or eyestrain. I have several co-workers who routinely turn off office lights (which I'd prefer to be even brighter) and replace them with dim uplighters.

Also, I'm not at all sure that my personal subjective experience is a robust effect.

The effect of lighting on human productivity is the canonical example of a difficult-to-study phenomenon. The Hawthorne Effect - where research shows an effect of an intervention because some research is being done - is legendarily named after some studies in to the effect on factory productivity of lighting. The story goes that increasing lighting increased productivity - and then changing it back to what it was before also increased productivity. The truth is a little more complicated than that - the Wikipedia article on the Hawthorne Effect touches on some of the issues - but it remains an elusive phenomenon. Also, pretty much all the 'research' I can easily put my hand on is obvious puff pieces by lighting companies, or companies showing off how much they have improved things by changing lighting.

Any self-test is hard to blind; as others have noted, a change in lighting is likely to be particularly hard to blind even if you have a separate experimenter. However, perception of brightness is to some degree relative (we judge how bright it is at least partly by comparison to how bright it was where we've just been), so with a bit of careful design it could be made less obtrusive - e.g. switching identical-looking bulbs while the subject is out of the room, and have the subject come in through an anteroom that has very low lighting so the experimental room will always seem bright, even if it's normal level.

I like the experimental ideas. With large enough n, one could have completely separate groups such that they aren't even aware that light is the experimental variable. But I don't run a psych department.

With the understanding that I only have a few minutes to check for research data: - "cognitive response ... to light at levels as low as 40 lux, is blue-shifted"

Sample sizes are dismal, but at least they tried. Thanks for looking this up!

Thanks for a useful practical tip.

the color of the light doesn't actually make a difference. The amount of light does.

Is that your own observation, or the result of broader research ? I always wondered if light "temperature" did affect mood/awakeness and found contradictory results when making a quick search, so I still have a blank spot on my map on that.

Just my own observation, and I was only comparing the full-on white I got to the bluish light they sell for light therapy. I don't know about those yellowish fluorescent lights.

What (probably) counts is Photosensitive ganglion cells and those do react more strongly to blue or violet wavelengths.

You can get CFL bulbs at the 105-watt level, and they're huge but bright and daylight-balanced too.

I recently bought this:

Unfortunately out of stock now, but it was under $30 for a 2-pack at the time. Note that I had to discard a smelly 65W bulb from Square Perfect, but LimoStudios seems able to handle its own heat. 2x 105W CFLs makes a brilliant blue-white light that does seem a bit like daylight.

If anyone knows of a floor lamp that will shade standard-socket light bulbs that are literally a foot long, I wouldn't mind a recommendation. My current setup is kinda hacky.

4 pack, 65 watt, Premium Loadstone Studio Day-Light Studio Light Bulb. Looks like the same brand of bulb. $23.70 shipped. The 65 watt bulbs are cheaper per lumen, and more efficient in lumens per watt.

Note that although the Square Perfect bulb also had the green band, just like LimoStudios, the Square Perfect bulb gave a dreadful smell and the LimoStudios ones didn't.

Square Perfect 65 watt bulb

The Lime Studios lights are at least not labelled as Square Perfect, and are listed as 6500K instead of 5500K. But I to think that any product that looks the same except for labeling come from the same manufacturer, but marketed through different outlets with customized labeling.

Probably still the same lamps. Maybe Square Perfect got a bad match. Maybe you just got a bad bulb. Or maybe it's a design flaw. The fact that they're cheaper than others gives me some pause that they have a problem. I was hoping the relative inexpense was an economy of scale issue with the most popular size.

But when they come in, I'll report back on whether they smell.

these look like a significantly better deal than anything I've seen on ebay or amazon.

I've noticed the same effect after installing 240 watts (that is, 25kLumens) of LED lighting in my living room. I stay more alert while they're on, and then pretty much crash when they turn off or I leave the room.

That was for an aquarium, though, and that much lighting actually is pretty expensive up-front.

If I gain say an hour of productive time on average, that benefit from that far exceeds the one-time cost of lighting.

Thanks for the data point.

LED prices just haven't come down enough yet.

I got halogen-buffed incandescents for the price, and because I was afraid fluorescent lights, if packed too close, might destroy each other and release that mercury.

LED lights are currently very slightly cheaper than any other type of lighting, amortized over the full lifetime of the lights. It'll probably get better.

Accounting for future value of the money, of course, it's more expensive. I'll take that over having to keep changing the lights, though.

Also, if you buy RGB(W) LEDs and add some work, you can choose your rooms color temperature at will. Keep it at 6k if you want to work, let it shift gently to 2k3 to help with a regular sleep rhythm, make it turquoise for a party...

Four CFLs in a cluster will be at least as happy as four incandescents in a cluster; possibly more so, given the much lower heat dissipation.

That's only true if they're built to tolerate heat as well as incandescents have to. Do you know they are?

Ooh ... good question. I have no idea.

Mind you, my experience of CFLs is that they blow out well before their claimed lifetime anyway on the crappy electricity we have around here. But I really, really like having daylight spectrum bulbs.

The aquarium? Or the lighting?

You probably meant the latter, but I'll answer both, just because I enjoy talking about aquariums. :P

Okay, first: The lighting is made up of six Grobeam 1000ND LED tiles. They're not cheap, and their spectrum is somewhat bizarre by living room lighting standards; they're tuned to deliver maximum useful light to plants, per watt, not for reading by. It's definitely not black-body.

They perfectly well do work as living-room lights, unless you're a photographer, but you should probably consider other options if you're not trying to grow plants. Cree also makes LED modules designed for wide-angle lighting, which these are not.

The actual aquariums look like this. There are two tanks, each with three tiles, or about 12000 lumens of directional lighting each. It's not quite at the level of daylight, but the amount of light that spills out is already enough to have a noticeable effect, so apparently it doesn't take extreme measures.

I got the tanks from a custom-tank-building outfit here in Ireland, along with about forty kilos of sand and fifty of gravel. The substrate is mostly mud, made using topsoil (gardening shop), kalium chloride (homebrewing website), clay and dolomite (pottery shop), with a thin layer of said sand and gravel on top.

The twisty wood is from a local fish shop. So would the fish be, if there were fish yet.

Lastly, about 1000 liters of tapwater...

If any of you followed me this far, you're probably interested in aquariums. I'd be happy to provide any advice I can, if you want, by private message. :-P

I was primarily interested in the lighting, but your aquarium is pretty awesome, too! :)

I think it'd be interesting to do some formal data collection on this idea even if there isn't going to be any control group. If you would, please PM me or comment in this thread if you're planning to try it out, and I will contact everyone who said they were trying it out in a few months and put together a short report.

Edit: Or put your email in this form.

Um - why not get a control group? I'd happily volunteer.

I mean, it might not be perfectly randomized, but you can at least watch for confounders from just being in this community, or introspecting for data collection, or whatnot.

Well, I've got a grand total of 3 emails and no PMs so far. I was going to ask questions like: how much time and money did the lights cost to set up, do you feel like it works better than coffee, have you seen any decline in its effectiveness, etc. No heavy data collection, just a survey about peoples' experiences.

Looks promising. How does your setup compare to light therapy devices such as the GoLite?

David Chapman has a neat method for getting a very large amount of light/lumens very cheaply in upfront & operating costs: use LED light bars sold for vehicular use and rewire them for normal household electricity consumption.

I found a cheap lux meter helpful in convincing myself to actually make a change in my lighting. I moved my workspace lighting from 130lux at my desk to 500lux , and have found it easier to stay alert in the evenings.

I believe it also improved my ability to judge indoor lighting levels, but haven't tested this.

Oh wow this is so obvious in hindsight. Trying this asap thank you.

If anyone is curious, my estimate of a potentially similar effect based on the weather would require a self-experiment of only ~70 days. I hope someone does run one.

EDIT: with additional data, the correlation has shrunk and so the necessary n has increased substantially to 1600 days.

Weather has too many confounders.

Birdsong, for example, has quite apparent anxiolytic effects.

Er... yeah. Confounders are why we would be interested in running a randomized experiment in the first place, and hence be interested in issues of experiment design like how many days of data we would need.

Good thing you reminded me.

I've had problems with motivation and mood.

I had a light box that I set across the room for a month, and my mood and motivation both improved. Got out of the habit of using it.

I've noticed a stimulating effect for the rest of the day just from being in the Home Depot lighting department for 20 minutes.

Another SAD light treatment I haven't tried because it's annoyingly pricey (~$300) for the materials involved:

Valkee Bright Light Headset Valkee substitutes the mood-elevating effects of the sun, by channeling bright light directly to photosensitive regions of the brain through the ear canal. That’s why Valkee increases energy, and can act as a preventative or treatment of mood swings. Valkee is used daily for just 6-12 minutes.

Valkee has CE Class II(a) medical device certification and is clinically tested.

Basically, the light form a couple of white LEDs pumped into your ears. I feel a little eyestrain from the light box, and find it inconvenient at work. They say to use it for 6-12 minutes, but I'd probably overdo it and try them during the day.

How much did this cost you?

The cheapest solution for very bright light that I'm aware of is something like these photography bulbs: ($15/bulb, ~4500 lumens from each)

but I'd be interested if others have found cheaper solutions.

I went with the KAEZI 85, as recommended in the top rated review on the parent's linked one.

I opened the box around one of my roommates, and we were both astounded by how huge it was. "It looks like you're building a death ray!" he exclaimed, to which I responded, "No, it's a life ray."

Here's a comparison of it and a regular bulb (in the lamp I'm using it in now, which may get replaced), what it looks like off, and what it looks like on (there is no other change in lighting between those two shots). The camera, of course, is overselling the difference- I can look at it directly for brief periods, but I prefer for it to be behind or above me, or in the very periphery of my vision.

How is your uber-bright bulb setup working for you? I'm trying to decide whether to invest in the necessary stuff to try it out.

If you're going to try bright light, I recommend the bulb I bought. It fits in normal sockets, uses a reasonable wattage, the light it generates is pleasant enough, and it's cheap.

Changes in energy have been small, and most noticeable in the mornings. I have not compared against, say, my goLITE, largely because I don't have a precise enough way to measure energy, but subjectively it seems comparable / possibly more effective. Given the tiny cost involved, I think it's worth trying, but subjectively it isn't revolutionary. (More careful statistics might show a larger effect.) It does seem effective at helping me stay up late, but since that's something I don't want, making sure to turn it off at a reasonable time is a recommended habit.

Yep, I had some trouble dealing with it because it's so bright - had to put it on a high shelf (we can't attach it to the ceiling). We've also found that they run quite hot compared to regular fluorescents.

There's a review on those that mentions a comparison of others. I have the Alzo 45w bulbs that are $10/per (used to be cheaper, they are now more $/lumen than the ones you linked) But I have no basis for comparison in terms of lumen/efficacy in increased attention.

It's funny. I use F.Lux both on my phone and computer and turn on my light to help wake up in the morning but I've never really thought about optimizing with more than averagely bright lights.

At night F.Lux is usually great. Except when waking up or doing polyphasic (where you actually treat night and day as the same thing). I discovered the program a week after I started Uberman, and a shortly after installing it, I started having trouble staying up during the early morning hours between 3am-7am, where previously I had no issue at all. I am no longer doing polyphasic, so it's awesome - I never get blinded by my monitor etc. I only wish I could make it so that it uses the daylight setting if I turn the PC on at night - so it helps me wake up. As it stands, I get two hours of "you should be in bed" lighting before it finally gives up on sending me for a nap.

I only wish I could make it so that it uses the daylight setting if I turn the PC on at night.

Use the 'disable for an hour' option, and repeat as needed.

Wow. Thanks for the idea. Just got instantly sleepy in around 20 seconds after installing it...

Good stuff. i recommend daylight-spectrum CFLs - about £5 each off eBay for 22W (100W-equivalent), compared to £2 in the shops for the horrible yellow 22W. I fill my house with these, and they really are just so much nicer than anything that isn't daylight-spectrum.

I have the alzo 45w and they're not that bright. You might want to try the higher wattage ones.

We since got five 30W (allegedly equivalent to 150W incandescent) 6400K bulbs and it's just lovely. Really increases my alertness for work-at-home days.

I bought these with a 4 socket adapter. However, I think my lamp can't power them all. Does anyone know a higher output lamp?

Actually I'm not even sure if that is how lights work. If someone can explain how I can the power that goes to the light bulbs, it'd be greatly appreciated.

Have you tried using normal bulbs of lower wattage in the 4 socket adapter?

(Honestly, the lower wattage shouldn't make a difference, but just in case it does...)

Most of the comments on this thread are about people who seem to find this useful or think that this will make a difference positively. While I think the idea interesting, and would like to try it out, I am one of those who don't seem to like really bright lighting. In fact, at work, I've had some of the overhead lights removed to make it generally less bright ambiently. I tend to suffer from eyestrain or seem to get a headache, though now that I think about it, I am not sure if this was because the over head lights were reflecting badly off of my computer screen or not.

Anyway, I'd like to get the opinions of and comments from people who generally turn off lights at work (such that the ambient light source is behind the monitor) , and likewise, even better if they have tried this out.

If using your computer in bright light gives you eyestrain, it might be possible that you need a brighter monitor to go with your brighter lights.

I like to make things dark so I can sleep better; I currently sleep with my head under multiple blankets. This means that I don't actually get any light in the morning until the blankets come off of my head. And that causes its own set of problems.

The sleep mask I got is a hot candidate for the Best Three Bucks I Ever Spent Award.

It seems like a sleep mask will either cause the same kind of problem as the blankets, or be ineffective. (And I like my blankets!)

Also, I often actually do want to sleep late without the sun interfering - going to bed at 4:00 AM and rising with the sun doesn't sound pleasant. What I'd really need a bright light on a timer or something; if I actually cared, I could probably get my father to rig something up for me.

Consider buying a really good one, like a Mindfold?

Mindfolds are brilliant for sensory deprivation, but the plastic makes them a bother for sleeping.

I used it for sleeping very happily while I was in the US, but tastes differ!

In recent months I have been going to my doctor about a sleep condition- I frequently and uncontrollably fall asleep at a particular time of day (about 8pm to 11pm). In my own experimentation I have found that bright light is one of the best ways to deal with this. In fact I am considering moving in order to help, as my current apartment has only lamps.

105 watts of incandescents with halogen gas, billed as the equivalent of 130 watts of incandescent light. And I got an adaptor like this that lets me screw four of those into the same socket in the ceiling.

I'm unclear on the physics of lightning. If you have four lights that are the equivalent of 130 watts each, is the light output equivalent to a single 520 watt light? Or is there some sort of nonlinear effect?

"Equivalent watts" is not a well-defined unit and the figures given by manufacturers are often exaggerated. Real incandescent bulbs vary in light output per watt. It's easier to use lumens, which are additive. However, human brightness perception is logarithmic, so 4 times the lumens will appear less than 4 times as bright.

Depends on how the bulb is build. The important factors are

  • light temperature: color tone; the temperature at which we would perceive a black body radiator to be of the same color
  • color rendition index: how good its light spectrum is compared to a black body, meaning if it doesn't miss any frequencies which we would perceive; incandescent bulbs have 100, good LEDs about 90, and currently average at 80 for living room LED bulbs
  • lumen/watt: efficiency as in perceived brightness per watt; not efficiency as in electric energy -> photons conversion

Most old-style incandescent bulbs have a simple build, and higher watt bulbs usually have a higher color temperature, and somewhat better efficiency. So, 4 60W would be severly different from 1 240W (such bulbs have been sold in the past, though not anymore; people prefer halogen for that now, because higher temperature incandescent bulbs usually have a much shorter life).

Halogen bulbs (I am always talking "quarz halogen" here; without Wikipedia I wouldn't have known others exist) are usually build for a specific temperature, and then you buy the wattage/brightness in lumen you want (where I live practically all halogen bulbs come in 2900 +/- 200 K); so you buy spot with 2900K, and have available everything from 10W to 40W, or a 300W "stick", again with 2900 K. Higher color temperature are available, but usually not at your first supermarket. BTW, you get around 4900 lumen for a 240W halogen stick.

With LEDs and CFLs everything gets fucking crazy. Whatever color temperature you prefer, don't get below a CRI of 85. It makes pictures look crazy, and after a while you want to rip out your eyes. 90 is really good, for professional photo work only 100 is 100.

Another guide for room lighting (personal experience): 2 klm at 20m² is just a bit more than cozy, 5 klm per 20m² are good enough (you can read, learn, work), but not office style. If the OP means "small room" at about 15 m², he should have the equivalent of 12 klm at 20m², which sounds about right for "feels brighter than winter outside", but it would not be (at 47 degrees north, that is).

Although having real bright light matters, to feel brighter you might want to make contrast. Your eyes/brain tell you "less bright" if everything has the same luminosity (that is the reason why on a cloudy day it feels darker on the outside than in your apartment, but as soon as you take a photograph you recognize it isn't). So: Get a dark spot somewhere.

Also note that sales of incadescent bulbs stronger than 60W are now forbidden in the EU and perhaps even some non-EU countries because of environmental concerns (incadescent bulbs being fairly inefficient at converting electricity to light). I used to import 200W bulbs from Russia to EU before they were banned in Russia as well.

Hi, that's technically incorrect. It's forbidden to sell them as a general home light source, it's legal to sell them for special uses. The net result is that you can still buy them everywhere (supermarkets, online, etc), only they're labeled as a "shock-resistant light bulb, not for home use" or as a "glowing electrical heater". The price is up about 5% and quality is slightly lower (shorter life) as now they're all from China, local factories were unfortunately closed following the ban. Overall, it's a ridiculously dead law.

If you live in eu country and you really can't buy them locally (which would be really weird), I guess I could buy some and send them to you

I could probably buy them locally if I tried enough but they are certainly not everywhere. The "glowing heater" versions, when found, are often darkly coloured to reduce the glow to a level which makes them useless as light source. The law isn't completely dead around here. My main problem is that it is difficult to obtain an equivalent of a 200W bulb, since such strong fluorescent or LED sources aren't generally available.

I would expect this to be the case in Germany, but not in Czech Republic, as I have now looked at your profile. In Poland they're as available as before the ban and the only difference is a "not for home use" sticker added or printed on a box... when laws are stupid it's good they're being ignored. :)

I've populated my house with 30W 6400K fluorescents, which claim to be 150W equivalent. Put two of those next to each other. (One is bright enough for me in practice, fwiw.)

theoretically yes... supposing that the smaller and bigger light sources are of equal efficiency and have the same spectrum. The number of photons emitted adds up linearly after all (I think it even works if the spectra are different.)

In practice, as it turns out (... "let's read lots of wikipedia about lighting" project), a 100W bulb produces roughly 1.5 times more lumens per watt than a 40W one, so the "equivalence" is also somewhat questionable... as it's the lumens that count (that being "the perceived lightness that is radiated").

(This thing is called "luminous efficacy", by the way. Am I the only one who thinks that it would make a nice LW post title at first look?)

I don't like light.

I have noticed that once it gets dark outside, I have to turn on the light in my room to be at all productive.

I wonder if wiring bright lights to turn on automatically will lead to more alertness in the morning. I find alarm clocks jarring and the first 5 minutes of being awake feels awful. Perhaps having light wake you is more natural?

The Zeo sleep manager has an option where it will play an alarm noise at a point in your sleep cycle when you're close to awake anyway. (It monitors N minutes prior to your alarm time, watching for you to enter light sleep, where N is configurable.) Works well for me.

Has anyone tried a accellerometer based sleep cycle alarm clock smartphone app?

A common kind of alarm clock is just that: lights turning on gradually in the morning to try to approximate dawn.

Try drinking water and a bit of pickle juice. Had a dramatic effect on my morning grogginess.

Does anyone know if there are links to purchase some of this online?