Weekend Diversion: The Light that's Right for Night

"As far as we can discern, the sole purpose of human existence is to kindle a light in the darkness of mere being." -Carl Jung

During the daytime, light is plentiful and abundant, and the majority of our waking lives are optimized for that. But more and more of us are active late into the dark hours, when -- as Owen Pallett (formerly Final Fantasy) would tell us -- the last of

Your Light is Spent.

Unfortunately for us, our bodies are accustomed to certain types of light during the day, and expect a different type of night at light.

Image credit: TableTop Studio Ltd or LLC.

Because there's a strong relationship between the types of light we see and the temperature of the body that emits light, our eyes perceive bluer lights as correlated with daytime (under normal circumstances) and predominantly redder lights as suitable for times closer to dawn/dusk, or even during the night.

Image credit: Wikimedia commons user Sch.

That's why blue, night-vision-ruining headlights are so obnoxious on the road; they've got the wrong color spectrum for a night environment.

That's also something that many household lights struggle with: their spectra make it difficult for your body to adjust, particularly at night. Whereas the old incandescent bulbs often ran at a low, night-suitable temperature, many of the fluorescents more common today emit bluer light, and contribute to people's ubiquitous difficulties in getting to sleep.

Image credit: © 2008-2012 MyLEDLightingGuide.com.

Astronomers and backpackers have figured this out; if we don't want to ruin our night vision or mess up our body's night/day internal clock, we would do well to change the color/temperature of the light we use after dark. That's why many experienced backpackers and amateur astronomers use exclusively red lights after the Sun has gone down.

Image credit: 2011 Grand Canyon Star Party, via http://www.valletravel.com/.

But what about our computer screens? Unsurprisingly, the colors our computer monitors emit -- and this includes phones, tablets, laptops and desktops -- are by default optimized for daytime use. But like most of us, I use my computer just as much after dark as I do during the day. Furthermore, too much staring-at-the-screen sometimes gives me headaches, and with NaNoWriMo coming up, it looks like I'm in store for even more.

Luckily, I've just discovered what promises to be a well-needed source of relief.

Screenshot from http://stereopsis.com/flux/.

Have a look at Stereopsis.com's new program, f.lux, which automatically adjusts your computer/screen's color display dependent on your time and location.

For an example as to how this affects me, here's a shot of what I use as my daytime settings.

Screenshot of my f.lux daytime settings.

Now, compare that with what I'll see at night, based on my custom settings.

Screenshot of my f.lux nighttime settings.

The difference is plain for all to see, but since I've started using this earlier this week, I've been able to get to sleep more easily even when I'm on the computer late at night, it drastically reduces my eyestrain, and best of all it doesn't cut down on readability or usability at all! I highly recommend getting it to anyone who doesn't know about this, and wish everyone not just a glorious weekend, but quality days and nights in all the days to come!

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The one I use is called Redshift, basically the same thing, but it happens to be available in the standard software choices for Fedora. And, it happens to have an astronomical-themed name. (Not that f.lux isn't, but it's less obvious, maybe.)

By Randy Owens (not verified) on 07 Oct 2012 #permalink

Oh, and I should have included a link for that. It's experimental for Windows, and not available for Mac or iOS. It specifically credits f.lux as its inspiration; apparently, back in 2009, f.lux kind of sucked on Linux, to hear him tell it.

Anyway, the link: Redshift

By Randy Owens (not verified) on 07 Oct 2012 #permalink

Guess this could be useful for someone who doesn't really care about color accuracy. But in my profession (graphic design) a calibrated screen which keeps it's color temperature as constant as possible, is a must. It's funny how are eyes are "thought" different things. My eyes get "irritated" when I see hints of yellow/red or blue in what is suppose to be white. Also if I see tinting of other colors in what is suppose to be grey. :) But for everyone else, this might work. Personally I just dim the screen brightness come nighttime on my laptop, and it's ok. But I don't find my desktop screen irritating my eyes, even when night comes. I do find tn-panels irritating, instead of IPS ones :))

By Sinisa Lazarek (not verified) on 07 Oct 2012 #permalink

Ubuntu is not Linux. I would like to see it in the Debian repositories. I'll see what I can find.

1) Ubuntu most certainly is Linux. It's not all Linux, or synonymous with Linux, but that's not the only meaning of "is". In this case, it's a subset of things that are Linux. Unless you mean the ridiculously strict sense in which Linux is only the kernel.
2) Who even mentioned Ubuntu, anyway, other than the external websites saying yes, it's available? Much less implied or explied that they're synonymous?

By Randy Owens (not verified) on 07 Oct 2012 #permalink

not to mention that it's also available for:
Arch Linux
Frugalware Linux
as well as Ubuntu - so what's the problem?

By starskeptic (not verified) on 07 Oct 2012 #permalink

I've been using f.lux for over a year now, and I can highly recommend it. It's absolutely perfect for when your screen is your only lightsource/late night readings etc. Try turning it off after an hour and you'll really notice how much worse it is for your eyes,

By Jonas Larsson (not verified) on 07 Oct 2012 #permalink

I'm sorry, but this is only half right.

First of all, as to the biological day/night rhythm (and messing it up with artificial light): There is research indicating that it is the primarily the absolute amount of light in the blue spectrum that seems to mess up our biological clocks – so, yes, color temperature matters here, but not so much.

And secondly, the red light is (more or less) monochromatic and has no color temperature. And secondly, the red light is used to keep night vision has more to do with cone cells and rod cells, and their spectral response – and not so much with the color of daytime sun light.

So these two effects are (a bit) independent.

BTW: The "correct" evening light with a "low temperature" seems to have been fire during evolutionary times, which seems to be close to incandescent light. On the blog "Mark's daily apple" there is some information on that (and more).

By Idiotic Climat… (not verified) on 07 Oct 2012 #permalink

Not quite true.

You can give the spectral response of a laser light a temperature even if it is monochromatic (it would then be a colour temperature). You can also give it a temperature of the intensity or power output that would be the equivalent of the power output by the light source if it were a black body.

And High Pressure Sodium Vapour is a wider spectrum than monochromatic.

None of which have anything to do with the flourescent and LED lights used on laptop/desktop screens.

They are broad spectrum but not blackbody. And dimming them reduces the light output but not to any useful extent the colour. Hence you need to calibrate.

Or use a palette for night time. Not so useful on Windows where many dialogs and programs will ignore the system palette and use their own (including the window decorations which is one problem with windows not being a proper window manager).

While waiting on grad school, I get the awesome chance to be a stay at home dad. My daughter has one of those light up bugs that casts stars around the room in 3 colors: red, green, and blue. I like the way blue looks, but I've found using red at night doesn't wake her up at all, really, while the others almost always cause her to stir at minimum. But the red also works best (as I learned backpacking) for seeing what I need to in her room even if I have to look directly at the light source several times.

I did not know about the adjustment toward my own sleep, though. I will definitely try to use this in the future.

What is Galileo is doing tonight? My hope would be that the great man is resting in peace and that his head is not spinning in his grave. How, now, can Galileo possibly have peace? So few scientists speak out clearly and loudly regarding whatsoever they believe to be true about at least one root cause of the distinctly human-driven global predicament looming so ominously before humanity: human population dynamics and its relationship to the human overpopulation of Earth. The human community could soon be confronted by multiple global threats to human wellbeing and environmental health that appear to result directly from the unbridled overproduction, overconsumption and overpopulation activities of the human species now overspreading the Earth and threatening to ravage the planetary home we are blessed us to inhabit? Many too many leaders and a predominant coterie of the' brightest and best' experts are choosing to remain silent rather than acknowledge science. Please consider how the elective mutism of so many of the most fortunate and knowledgeable elders among us could be contributing mightily to the ruination of Earth and its environs as a fit place for human habitation.

Where are the intelligent leaders and established professionals with appropriate expertise who will stop colluding in silence, who are willing to examine and report on science that exists in solid research and validated empirical data? Look at the dismaying disarray in which we find ourselves now and how far we have to travel in a short time to move the human family away from precipitating some unimaginable sort of global ecological wreckage. What would the world we inhabit look like if scientists like Galileo had chosen not to disclose science and instead adopt a code of silence? In such circumstances Galileo as well as scientists today would speak only about scientific evidence that the super-rich and most powerful people of the day believe to be politically convenient, religiously tolerable, economically expedient, socially correct and culturally prescribed. By so doing, Galileo and modern-day scientists would effectively breach their responsibilities to science and duties to humanity to tell the truth as they see it, as best they can report it.

Heretofore hesitant and inert scientists are called upon now to follow the good example of Galileo. The politically correct silence of so many knowledgeable but apparently dumbstruck experts on one hand as well as the incessant mass media jabber of sycophants and other minions of wealthy power brokers on the other hand could be killing the world we inhabit as well as life as we know it. Most scientists have not actively engaged in inimical ‘sins of commission’, as have many too many deceitful, chattering experts; and yet too many scientists on our watch have chosen to maintain their silence by not speaking out ‘as if each one was a million voices’. It appears scientists have been and continue willfully to deny the best available scientific evidence that specifically regards human population dynamics. Is their collusion to remain electively mute correctly described as a sin of omission? If science does not overcome silence, then much of the world the human community believes we are preserving and protecting will be irreversibly degraded and unknowingly dissipated, if not destroyed outright. Surely, truthful empirical reports from intellectually honest and moral courageous scientists regarding the population dynamics of the human species and the human overpopulation of Earth will give Galileo Galilei peace.

By Steven Earl Salmony (not verified) on 08 Oct 2012 #permalink

I don't think Gallileo has anything to do with overpopulation or ecological pressures on growth.

And given the overwhelming majority of science bodies who are NOT cowed to keep quiet about AGW rather disproves your rather long winded and rambling discourse, at least as far as I can discern any thread of thought to it.

@Wow Whilst I am much closer to you than Steven on this, my impression is that "science bodies" in general seem to pussyfoot around the important issues arising from AGW. The real problem is not that the over-consumption of several hundred million people is responsible for the damage, but that six billion others (and rising) aspire to their lifestyle. And who are we to say they can't have it. Any proposed scientific solution that fails to acknowledge emissions are the product of per capita consumption and population is doomed to failure. Both have to be addressed whatever the political implications.

Not really, David. The IPCC, being required to get consensus and required moreover to include politicians input on how to present the science to the public, the summary for policymakers pussyfoots.

The politicians themselves play the "all mouth, no trousers" card too, mouthing at best how things need to be done to combat AGW, but not actually doing anything substantive about it.

Since the scientists have no power to make policy, their stance isn't what is causing the lack of change.

f.lux, AFAICT, is only available from an Ubuntu PPA. There are command-line versions that will run in other distros, but not the GUI. I did find redshift in the Debian repositories, which does the same thing, optimized for Debian. It's also available for other distros, including Ubuntu.

Saying Ubuntu is not Linux means it's not all of Linux, obviously. It's one of many distros, although some true believers seem to think it's the only one that matters. The Linux religious wars will probably never end, silly as they are.

Linux is the kernel.

Ubuntu is a GNU system built on the Linux kernel.

It is GNU/Linux.

Meanwhile, Android is uses the Linux kernel but the user system is not, it's Android.

And the same people who complain about RMS insisting people call Ubuntu et al "GNU/Linux" also manage in large part to prove him right by complaining that Android is not Linux and they're breaking the law by not releasing Android.

Android is not Linux.

Ubuntu is not Linux.

They both use Linux as their kernel.

But people shorten it as if the kernel is all there was. And so people get confused. But still mulishly berate RMS's "It's GNU/Linux".

And I, on the other hand, am totally on board with RMS' claim that it should be called GNU/Linux, yet nevertheless sloppily use "Linux" to refer to either just the kernel or the complete system.

Also I call it "Lih-nucks" even though the correct pronunciation according to Linus Torvolds is "Lee-nooks" as one would expect given his/its country of origin.

Now for a more relevant comment -- I'm well aware of the effect of color on night vision, but never really considered its possible effect on sleep cycles. I personally really like the bright white CFLs and started replacing some of the lower temperature ones with them. Maybe I'll have to reconsider? But it really brings out the blue in the walls!

"yet nevertheless sloppily use “Linux” to refer to either just the kernel or the complete system."

Do you confuse the distribution with the kernel, though, which is the origin of the little spat about "Ubuntu is not Linux/is too" just here.

I'll try this. Interestingly, quite a number of animals (I keep hens) will sleep undisturbed under a red light.

By Chris Harris (not verified) on 13 Oct 2012 #permalink