@bridget For future reference, if you go to the "f.lux" support on the forum, it gets broken down by operating system, Windows, Mac, Linux, and others. It's not exactly consistent between windows and OS X.

In windows 7 and above (and even vista) if you do not see the yellow and blue icon by the clock, anywhere, just click the little white triangle so you can see the extra "hidden" icons. You can then drag it out of the box. What I like to do is go find it in the all programs list. Right click on the "f.lux" entry and say "Pin to taskbar". This makes the icon larger, and more detailed, and you get to show off that you have f.lux installed!

For OS X, it literally should be left of the clock. It's not exactly the most stand out icon, but almost looks like the analog clock option. It's an outline of the f.lux icon, with a (smaller) hill, and a half sun in the middle. If it's not there, then do the following:

Open Activity Monitor, and look for the f.lux entry (actually most likely called flux.

If that's not there, then do a finder search for f.lux, and start one of them.

I'm not sure I understand the question 100%, but here's how to use f.lux for sleep:

Set f.lux to a very warm color temperature (as warm as you can tolerate - I use 1200K) an hour or two or three before going to sleep (if you need assistance with setting f.lux to a super warm color temperature after sunrise, then I can help with that because I have to do it nearly every other day) You should also lower your monitor's brightness as much as you can tolerate during this time too. I set mine to about 10%, but I sometimes set it to 0%. Sometimes I even simply turn my computer off and do almost nothing in complete silence for an hour or so before going to sleep. It's like meditation, but with no specific focus on anything in particular, unless that's needed. The mind loves that freedom, so try it out if you're curious! It's a little bit like how you do your best thinking in the shower or on the toilet or whenever you're doing any other sort of mindless activity - but BETTER.

Getting back to the color temperature and brightness, that's only a part of what a person should do. You should also do the same thing with ALL light sources in your home, including things like your T.V. and mobile devices, etc. You see, f.lux simply makes it possible to use your computer before bed without being blasted by blue light. The problem with our modern world is, most light bulbs and T.V.s and mobile devices still blast us with too much blue light - and it's usually always WAY too bright to be using them before bed (only, the vast majority of people aren't aware of it). You also have to consider the brightness of these light sources.

So, let's say you are able to make all of your light sources produce a nice low-brightness super-warm color temperature and you are able to avoid watching the T.V.. Well that's great, but what about the computer? It's still going to be producing lots of blue light. That's where f.lux comes in. In today's world, most people use their computers right up to the last second before going to sleep. I do. So, I have f.lux.

Why is the brightness important? Think about a full moon for a moment. The sunlight that it's reflecting at us isn't a warm color at all, but it's not bright enough to really affect us even though its invisible energy is enough to affect us (that's a part of what makes sunlight energizing - it's not just the visible light). So, the brightness of all light sources needs to be lowered as much as you can tolerate, even if some of those light sources are fairly blue. After all, f.lux isn't a magic bullet.

Sound levels are important too because loud sounds can be just as "alerting" as bright blue light - sometimes even more alerting. So when I'm in that last hour or two (or three) before bed, I make sure I become quiet and I reduce the volume on my computer a lot too. I close doors quietly, I set the toilet lid/seat down quietly, I do everything quieter. It really makes a difference.

Of course, there's still more to consider, like the pace at which we do everything that we're doing in that last hour or two before bed. I mean, if we're rushing around trying to get ready for bed as quickly as possible, then of course falling asleep will be difficult. If we instead move slower and calmer (walk slower too) and practically pretend like we're super tired and can't move any faster than a snail, then falling asleep will naturally be easier.

Some people find that they lie awake for an annoyingly long time because can't stop thinking about the next day's agenda or To-Do List. The best solution to that is to physically write everything down using a real pen or a pencil and real paper, and put it somewhere near your bed where it's going to be extremely easy to review it when you wake up. The physical activity of actually writing it all down puts your mind at ease because then you can rest knowing that you can simply look at it when you wake up. Simply typing it into a computer isn't enough unfortunately because writing is more physical than typing. It's much easier for the brain to remember that you did it.

So yeah, f.lux is just a very small part of the big picture.

It is easier to adapt to see "white" when a screen matches its surroundings. Since most lighting systems try to match Planckian radiators (blackbodies), so do we.

The hope is at moderate settings you will see your screen as "mostly white, a little bit orange" and not "crazy green-purple".

There are three considerations for screen brightness and color shifting: 1) daylight (determined by sunrise, sunset, and sun height); 2) ambient lighting (whether you are indoors or outdoors, and whether the lights are on); and 3) the user's desired wake/sleep times. An ideal program will allow the user to fine-tune according to all of these considerations. For example, the monitor would automatically dim when in a dark room, but gradually, as the person (and/or his transition lenses) adjusts. It will also allow for those who unfortunately have to wake up before sunrise or work late night shifts. Also, you don't necessarily want to just limit the light levels to two levels. The indoor room might be a medium brightness with some blue light, which is different than the low blue light of between sunset and 2 hrs before bedtime, and then cut out all blue light after 2 hours before bedtime. The bedtime would be a set time on the clock and only change for daylight savings whereas the sunset time would vary daily with the actual sunset time.

@mbjerggaard Cold brew is a smooth finish without bitterness. It's like iced tea and hot tea, no requirement to choose just one. I personally really like both.

@melgo66 Well you need to have dim (more orangish yellow) colored light, such as a 25 watt light(or you can even go down to 15 watts if you want to get too crazy, it won't be much more than a bright night light), and use that when brushing your teeth, or getting some water etc. Also would be really nice in a bedside light.

@TwoCables Do NOT buy the Philips "SlimStyle" bulbs, I've seen they use a 240Hz flicker, so I never bought those--I bet the color isn't very good either. Also currently, don't use any Cree bulbs, or check with reviews that do study flicker before you buy. Yes there are video reviews that check for flicker, and I hope more people start doing that!

Giving advice like this is a little beyond our abilities, but I can happily direct you to a vey useful resource at http://re-timer.com/the-product/sleep-calculator/ - also go for their ebook, it is full of science backed advice for exactly what you're asking about.

@Daniel-AndAshley-Loveland When you're studying exams, it's very counter-productive to stay up late. When you do that, you won't sleep as well and you also won't remember as much. When you're tired, you're tired, just go to sleep. Especially at 1 a.m.

@Marcel-Wolthers Oh that's cool, how much light do you think it puts out? I just got a 200 watt bulb that lasts a really really long time (20+ years) that gets about as bright as a 150 watt bulb. It's decently bright, but of course very yellow still in comparison to the overcast weather I've been getting.

Endless Summer mode!

Endless Summer

See also: Dark north mode

I have not detected visible flicker from PWM on any of them, including Retina MBP, iPhone 6, iPad minis. iPad pro feels somewhat more flickery when using it. but it's not the flashy sort of PWM that makes your head hurt to look at. Some people are working on this issue, read up here: http://energy.gov/sites/prod/files/2015/11/f27/miller_gaines_flicker_portland2015.pdf

I have recently started working night shift, 8pm-6:30am and try and be in bed around 10am. I have tried to find a location that is almost 12 different from my current time as I keep my computer room fairly bright at night. I found having flux turn on around sunrise is best for me as I start to avoid the sun and hopefully trick my body into thinking it's close to bed time.
Since you stay up later, I would look for a time zone that triggers flux a few hours before you go to bed, and as I am sure you do, draw those curtains closed and dim those lights around the same time.

I really wish flux just had a time offset feature for us night people.

@Jeremy-Charms said:

My whole room colour is white but when i switch flux my laptop screen gets yellow, what to do

My solution is, stop using those CFL lights and get the warmest lighting you can find. I also recommend that you get red LED lights for swapping out every night (or at least orange...).

Here's what I do:

The only sources of light in my room that I use are two floor lamps (I have a super bright ceiling fan light that I use when I need it). The light sockets are at shoulder-height for me. I use the SWITCH brand 3-Way lights in these. When I'm about an hour away from "f.lux time", I turn these lights down to their lowest setting. This simultaneously allows them to cool down to a safe-to-touch temperature (the heatsinks get so hot that it would burn human skin almost instantly), and it helps me begin to relax.

After I know they're relatively cool to the touch, I unscrew them and put in my red FEIT LED lights:

http://www.feit.com/led-lamps/performance/performance_led/performance_led/color_leds/color_led/a19-r-led

These things are PURE red. They're a bit on the bright side though. If I close my eyes with both of these on and then alternate between "relaxed closed" and "super tight squeezed squint-closed", the difference in brightness coming through my eyelids is about the same as having my SWITCH 3-WAYs on at their highest setting: the 75W equivalent setting.

Still, with the pure red color, I can set f.lux to 1200K, dim my monitor to about 10% brightness, and begin the process of becoming completely ready to go to sleep. It takes an hour or two, but it works beautifully.

I've been doing this every single night for the past 4 months, and I LOVE it!! You would think that a person would get sick of unscrewing two lights and screwing in two different ones every single freakin' night, but I don't even think twice about it because my REASON for doing it makes me enjoy doing it.

Oh, one last thing: when I have maybe 30-45 minutes left before I want to get into bed, I turn off just one of the two floor lamps so that I only have one red FEIT LED light on. That is, I turn off the lamp that's closest to me while I'm sitting at my computer. That's because the lamp is so close to me that if I extend my right arm straight out to my right, the stem/pole of the floor lamp lines up with my wrist! That's a high Lumens level! So yeah, that light is the first to go off. Then when I'm ready, I turn off my computer, get into bed, lay down, and then I reach out from under my covers and turn off the 2nd floor lamp.

So yeah, I strongly and sincerely recommend that you try to achieve something like this. I wish that I had started doing this YEARS ago. It's never too late to start good and healthy habits though!