I hear so much about f.lux, but to me I don't know if the science quite backs it up like everyone says it does. I've found it suffers from the, "They used the word science so it must be good" problem.
Why hasn't anyone done a study on specifically what f.lux attempts to do? Sure, light at night causes people problems sleeping, but does f.lux actually make a difference? Can we quantify that difference in a way that controls for the fanboy (formerly known as placebo) effect?
>Effects of LED-backlit computer screen and emotional selfregulation on human melatonin production.
>[...] Finally, we can also report that the blue light of LED-backlit computer screen significantly suppress melatonin production (91%) more than red light (78%) and no light (44%).
sigh Fine, here are more articles. If you don't want to believe in peer-reviewed academic literature, I'm not sure why I'm bothering. Statistically significant results can be obtained with few participants. Behold the power of math.
Nocturnal light exposure impairs affective responses in a wavelength-dependent manner.
>Our results demonstrate that exposure to LAN influences behavior and neuronal plasticity and that this effect is likely mediated by ipRGCs. Modern sources of LAN that contain blue wavelengths may be particularly disruptive to the circadian system, potentially contributing to altered mood regulation.
Out of the lab and into the bathroom: evening short-term exposure to conventional light suppresses melatonin and increases alertness perception.
>Subjective alertness was significantly increased after exposure to three of the lighting conditions which included blue spectral components in their spectra. Evening exposure to conventional lamps in an everyday setting influences melatonin excretion and alertness perception within 30 min.
Non-visual effects of light on melatonin, alertness and cognitive performance: can blue-enriched light keep us alert?
Exposure to light at 6500K induced greater melatonin suppression, together with enhanced subjective alertness, well-being and visual comfort. With respect to cognitive performance, light at 6500K led to significantly faster reaction times in tasks associated with sustained attention (Psychomotor Vigilance and GO/NOGO Task), but not in tasks associated with executive function (Paced Visual Serial Addition Task).
[...]
Our findings suggest that the sensitivity of the human alerting and cognitive response to polychromatic light at levels as low as 40 lux, is blue-shifted relative to the three-cone visual photopic system. Thus, the selection of commercially available compact fluorescent lights with different colour temperatures significantly impacts on circadian physiology and cognitive performance at home and in the workplace.
i'm impressed with someone's ability to ask for someone else to do research, and then be snooty when someone finds it for them. I thought that the effects of blue light on circadian rhythms was clear-cut, popular knowledge.
This trickery may work on Reddit (I know you're from Reddit because you use carets to denote quotations), but allow me to repeat myself:
Why hasn't anyone done a study on specifically what f.lux attempts to do? Sure, light at night causes people problems sleeping, but does f.lux actually make a difference? Can we quantify that difference in a way that controls for the fanboy (formerly known as placebo) effect?
Haha, what? That is the most bizarre insult? argument? that I've seen in a while. People use greater-than characters all the time for quotations. It's been used in email forever. But bonus points for trying to be edgy I guess.
To your question: All the studies are basically examining the principle that f.lux operates on. Shift colors away from blue and you can limit the decrease in melatonin production. I don't understand your question?
If you mean, "why has no one done a study on f.lux itself?", then I'm assuming no one has done a study on f.lux per se because (I'm just guessing here) no serious academic researcher really gives two shits about a piece of software on the internet.
However, that doesn't mean their research cannot be applied. F.lux is applied science, working on a fairly solid base of academic research. Real science with, yunno, quantifiable and statistically significant results. It isn't "fanboyism" or "science"...it is peer-reviewed literature.
The articles I linked specifically talk about how spectral blue light decreases melatonin production (a hormone directly related to how sleepy you feel at night) and a corresponding increase in alertness.
Doing a little extrapolation, if you decrease the amount of blue light that you are exposed to in the evening you decrease the impact on melatonin production and increased alertness.
So sure, I doubt anyone has stuck a person in front of f.lux and measured salivatory melatonin levels...but they have done the equivalent with blue and red lights. It isn't reaching to say that f.lux is doing exactly the same thing.
Did you know monitors leak anywhere from some to a lot of white light, depending on age and quality (if you turn off the lights in your computer room some time and load up a black page, is it completely dark in the room? Ever wonder why not?)? F.lux can't change the color of that light, and so the question becomes: is that leaked white light enough to negate the benefit seen in the studies?
So I bet you can imagine my persistent confusion with your linking to what amount to irrelevant studies, when this question is the one I've been asking over and over again. When you say "have done the equivalent with blue and red lights", you are absolutely, 100% wrong. It is extremely reaching to say that F.lux is doing the same thing, if you know how monitors work.
> "Melatonin is a circadian hormone transmitted via suprachiasmatic nucleus (SCN) in the hypothalamus and sympathetic nervous system to the pineal gland. It is a hormone necessary to many human functions such as immune, cardiovascular, neuron and sleep/awake functions. Since melatonin enhancement or suppression is reported to be closely related to the photic information from retina, in this paper, we aim further to study both the lighting condition and the emotional self-regulation in different lighting conditions together with their effects on the production of human melatonin. In this experiment, five participants are in three light exposure conditions by LED backlit computer screen..."
I don't see anyone saying it's irrefutable. It's a conference proceeding, which means it's essentially a progress report on a line of research. And small sample sizes can produce compelling evidence if there is a large effect size observed, particularly with the objective physiological measures (subjective psychometrics are much more susceptible to bias). This research is also likely to be supported by other studies, making this essentially replication of an observed effect.
Look up how blue led light can disrupt sleeping. Ever notice how bright blue led is compared to others (red, yellow)? My cable modem has blue leds for the indicator lights, and in a dark room, it is amazing how bright they are.
f.lux makes your monitor use less of the blue components of light and more of the reds. It will make your screen look funny till you get used to it, which takes minutes. To really see what it does, in a darkened room, turn off f.lux
It doesn't "remove brightness magically", it just swings the color temperature of ALL colors displayed towards the red end of the spectrum, which studies have shown can decrease the inhibition of melatonin production which means you will be more likely to get sleepy around the time you're supposed to, whereas before you might not have until much later and disturbed your sleep.
What aren't you getting about this? There is leakage of white unfiltered light that comes from from most monitors (the super duper high quality monitors boast about low light leakage, but they still do it a bit). F.lux cannot possibly change the color temperature of this light. So my question is and has been, does that leakage have enough of an impact to negate the effects of F.lux? That's the question worth answering, because if it's, "No, the effects are negated by the white light leakage", then there's absolutely no point in using F.lux whatsoever.
That light is negligible. I have used F.lux for years, I swear by it, and if I bring an iPad or iPhone to bed and stare at it a while before I sleep (note: don't do this), I can totally notice the difference. (Then again I have a diagnosed sleep disorder and have to be extra careful about these things.)
The LCD in your monitor is a filter, that controls what colors from the white back-light reach your eyes.
It is not completely effective - when the LCD is set to block all colors, there is some white-ish leakage as you say. A completely red shape on an LCD would still have some blue in it from the leakage. We perceive color and brightness relative to the other colors close by.
Flux shifts the color balance of the screen towards red at night. After your eyes get used to it, the colors look about right, but the LCD is in fact blocking a higher proportion of blue than normal.
What it does not do is change the brightness of the screen - this is usually done by changing the intensity of the backlight. It is bad for you to look at a screen that is either too bright or too dark for the room you are in, so this is best done with an actual light sensor.
Here is a thread about doing that, but neither of the programs in it work very well. If you fancy making an open source program to do this, you'll be my hero :-)
When your monitor is displaying a white image, lots of white light is coming out. When your monitor is displaying a red image, lots of red light is coming out. F.lux makes white images tinged red. F.lux isn't about removing brightness in general.
Your clarification is confusing me even more, I don't understand what your confusion is at all.
When your monitor is displaying a red image, red light is coming out, but so is white light, because your monitor is not 100% light sealed. The backlight in your monitor is leaking through the edges of your LED screen.
So the question becomes, is that leaked white light enough to disrupt your sleep? No one's done any studies on this question, no one's looked into it, and so until they do, F.lux's effectiveness remains in question.
None of what you just said refutes any of the following: "When your monitor is displaying a white image, lots of white light is coming out. When your monitor is displaying a red image, lots of red light is coming out. F.lux makes white images tinged red. F.lux isn't about removing brightness in general."
Lets get some basics out of the way here, since you seem to be confused about either what "white", "blue", and "red" light is, or you seem to be confused about what f.lux actually does.
"red" light is light that consists largely or entirely of visible light with long wavelengths. "blue" light is light that consists largely or entirely of visible light with short wavelengths. "white light" is light that contains a good but not necessarily perfect mix of all visible wavelengths.
When you decrease the color temperature of an image, you are reducing the amount of short wavelength light, not eliminating it. LCD imperfection is frankly irrelevant as some short wavelength light is still coming through by design. If you removed all short wavelength light you would just be left with reds and blacks. That isn't what f.lux does, or claims to do.
> "So the question becomes, is that leaked white light enough to disrupt your sleep? No one's done any studies on this question"
Many studies have been done on the effects of different intensities of short wavelength light on sleep. This research isn't binary "blue light or zero blue light" For example, any of the studies which include an incandescent bulb cover this. Incandescent bulbs are black body radiators, they emit short wavelength light and long wavelength light, however the proportion of short to long wavelength light that they emit is much different from what florescent bulbs emit. (Specifically, light from incandescent bulbs is said to be "warmer").
By the way, one of polyfractal's links is to a study that used LCDs as the light source. Try reading before making an ass out of yourself.
The difference I use Redshift for is how much my eyes hurt at night the second I turn it off and everything shifts bluer. Whether or not it changes my sleeping patterns, I cannot say, but it is more pleasant at least.
Why hasn't anyone done a study on specifically what f.lux attempts to do? Sure, light at night causes people problems sleeping, but does f.lux actually make a difference? Can we quantify that difference in a way that controls for the fanboy (formerly known as placebo) effect?