Dimming screen brightness: flux or screen settings?



  • Hi,

    I have a general question regarding the use of f.lux, it's not really specific to Windows (although that's my OS):

    What's the best way to dim the brightness of my screen, through the screen settings or through f.lux (with the alt-pgdn/up keys)?

    My computer screen is a Samsung S24D390HL. I read that dimming a LED screen can introduce a flickering/stroboscopic effect but I don't know if that's true. And even if that was true, would there be a difference by dimming through f.lux rather than through the screen settings?

    Thanks in advance for any info :)



  • f.lux doesn't dim the backlight, it just increases the black level. It also lowers the color temperature slightly at the same time to simulate what happens to the color temperature of an incandescent bulb that's being dimmed. The brightness control is for adding to the effect of lowering your monitor's backlight and/or setting f.lux to a warmer color temperature.

    So, the only way you can dim the backlight is by using the monitor's onboard controls, or via MagicTune or whatever Samsung is using for their current monitors. Both of these methods will dim the backlight. If you get any flickering or anything else that's unwanted, you'll know it. There won't be any question about it or guessing or wondering.



  • @TwoCables said:

    If you get any flickering or anything else that's unwanted, you'll know it. There won't be any question about it or guessing or wondering.

    UH well, about that.... it actually takes a special eye (like me and @Lorna have, and probably two distinct causes at that) to genuinely see high rate flicker like 240 Hz. I think that's what most PWM monitors use.

    If need be, get a camera, as they are usually excellent at seeing it, but it may be displayed MUCH slower than it really is. If there are any lines flowing at a decent speed, then the monitor uses PWM, no question, even CCFL backlights use it, but it's a smoother style that I could never see in use.



  • @Tungsten_smooth said:

    @TwoCables said:

    If you get any flickering or anything else that's unwanted, you'll know it. There won't be any question about it or guessing or wondering.

    UH well, about that.... it actually takes a special eye (like me and @Lorna have, and probably two distinct causes at that) to genuinely see high rate flicker like 240 Hz. I think that's what most PWM monitors use.

    If need be, get a camera, as they are usually excellent at seeing it, but it may be displayed MUCH slower than it really is. If there are any lines flowing at a decent speed, then the monitor uses PWM, no question, even CCFL backlights use it, but it's a smoother style that I could never see in use.

    Yeah, but it doesn't bother everyone. Some people are completely 'immune' to it while others are sensitive. Sometimes it's just The Placebo Effect, where you are only bothered by it because you've seen slow-motion video evidence that your light or your monitor flickers at a high speed. So that's really why I said what I said. I think it's best to keep it simple.



  • @TwoCables Yeah but for me it's like someone waving 1000 small dark lines in front of what I'm trying to read, every time I scan a line of text or look or blink it's horrible. But it shows me who the cheap manufacturers are, so I actually prefer the ability to see it.



  • @Tungsten_smooth said:

    @TwoCables Yeah but for me it's like someone waving 1000 small dark lines in front of what I'm trying to read, every time I scan a line of text or look or blink it's horrible. But it shows me who the cheap manufacturers are, so I actually prefer the ability to see it.

    Ok, but the point is that it's all up to him to decide if reducing his monitor's brightness bothers him. Like, if that monitor is known to have flicker but he says it doesn't bother him or he doesn't notice it, then ok. Y'know? That's why I am recommending that he just go ahead and reduce its brightness. It's the only way to find out.



  • @TwoCables Yeah, that's really all we can do. Now, if they start saying they experience eye fatigue or blurry vision, I'd step in with TFTCentral.co.uk and help them, but I guess it ain't broke yet.

    Edit: And it's a non issue!: http://www.tftcentral.co.uk/articles/flicker_free_database.htm



  • @Tungsten_smooth said:

    @TwoCables Yeah, that's really all we can do. Now, if they start saying they experience eye fatigue or blurry vision, I'd step in with TFTCentral.co.uk and help them, but I guess it ain't broke yet.

    Edit: And it's a non issue!: http://www.tftcentral.co.uk/articles/flicker_free_database.htm

    Oh, yep: https://pcmonitors.info/reviews/samsung-s24d390hl/

    From the review:

    "PWM (Pulse Width Modulation)

    Unlike some other manufacturers Samsung do not specifically market this monitor as ‘flicker free’ or anything else to that effect. A nice bonus, though, is that this monitor does not use PWM (Pulse Width Modulation) to regulate its backlight brightness at any brightness and instead employs a Direct Current (DC) adjustment method. The backlight is therefore considered ‘flicker free’ which will be welcome news for users who are sensitive to PWM or worry about flicker on monitor backlights."



  • @TwoCables said:

    f.lux doesn't dim the backlight, it just increases the black level. It also lowers the color temperature slightly at the same time to simulate what happens to the color temperature of an incandescent bulb that's being dimmed. The brightness control is for adding to the effect of lowering your monitor's backlight and/or setting f.lux to a warmer color temperature.

    Thanks, I was wondering how f.lux decreased the brightness because it seemed different from when I use the screen controls.

    I am sensitive to light, looking at a screen at full brightness is, for me, like looking at a luminotherapy light: after several hours I get agitated and confused. Too bright? Too much blue light? I don't know but f.lux definitely makes my screen easier to look at, both for my eyes and my brain.

    At the moment my screen's settings are 54/100 for brightness and 45/100 for contrast (I set those with the help of some online display calibration tools). But even that is still too bright for my eyes so I've been using f.lux to lower the amount of blue light and dim the brightness even more. During the day I usually dial down the brightness one notch and warmth is at 3485K. Those settings are easy on my eyes and if I want color accuracy I can always disable f.lux quickly, I like that :)

    Before buying this screen I had read the pcmonitors review that you linked to. The technology was one of the deciding factor. But in terms of health I didn't feel any change compared to my previous monitor, or at least none that I could measure. I was already using f.lux back then and using f.lux really made a measurable difference, I can vouch for that.

    PS: in my original post I tried to include the pcmonitors link but my post was rejected as spam (this happened again with this post btw, that's why I just write "pcmonitors" without the rest of the address)



  • @Amun-Ra said:

    At the moment my screen's settings are 54/100 for brightness and 45/100 for contrast (I set those with the help of some online display calibration tools). But even that is still too bright for my eyes so I've been using f.lux to lower the amount of blue light and dim the brightness even more.

    (Forum hint: You actually have to do this quickly, if I wait too long you the links don't work for me at all--select some text you want to quote, and just click "reply")

    You may try reducing the brightness even further. As for the contrast, in the daytime, find the limit before the colors start to look odd or different, and write that down if you aren't likely to remember it. Then you can drop the brightness to 0, and bring down contrast even further if needed. In the daytime, you can just bring up contrast to the limit, and maybe that would be enough in the morning or evening.



  • @Tungsten_smooth said:

    @Amun-Ra said:

    At the moment my screen's settings are 54/100 for brightness and 45/100 for contrast (I set those with the help of some online display calibration tools). But even that is still too bright for my eyes so I've been using f.lux to lower the amount of blue light and dim the brightness even more.

    (Forum hint: You actually have to do this quickly, if I wait too long you the links don't work for me at all--select some text you want to quote, and just click "reply")

    You may try reducing the brightness even further. As for the contrast, in the daytime, find the limit before the colors start to look odd or different, and write that down if you aren't likely to remember it. Then you can drop the brightness to 0, and bring down contrast even further if needed. In the daytime, you can just bring up contrast to the limit, and maybe that would be enough in the morning or evening.

    Changing the brightness/contrast settings through the screen control pannel is cumbersome, that's why I was looking for an alternative, like f.lux, but I was afraid of introducing flicker or something like that because I didn't know how f.lux worked, that's the origin of my question.

    I'm actually trying to resolve a health issue: my right eye is bloated and the upper eyelid is red. I visited a lot of doctors but none could find an explanation. So I'm left looking for other possible explanations. My problem started when I switched from my laptop (and it's tiny 10.4" TFT screen) to a desktop with a large LED screen. But it could just be a coincidence, I've got other health issues that could play a part. Neither the ophtalmologist nor the dermatologist put the blame on the computer screen, maybe they're right but LED technology is relatively new, that's why I'm not discounting it outright. In any case my search has led me to discover f.lux, and just that has been helpful, I've been using it for the past 4 years at least and I now can't imagine myself working on a computer that hasn't f.lux installed.



  • @Amun-Ra said:

    @Tungsten_smooth said:

    @Amun-Ra said:

    At the moment my screen's settings are 54/100 for brightness and 45/100 for contrast (I set those with the help of some online display calibration tools). But even that is still too bright for my eyes so I've been using f.lux to lower the amount of blue light and dim the brightness even more.

    (Forum hint: You actually have to do this quickly, if I wait too long you the links don't work for me at all--select some text you want to quote, and just click "reply")

    You may try reducing the brightness even further. As for the contrast, in the daytime, find the limit before the colors start to look odd or different, and write that down if you aren't likely to remember it. Then you can drop the brightness to 0, and bring down contrast even further if needed. In the daytime, you can just bring up contrast to the limit, and maybe that would be enough in the morning or evening.

    Changing the brightness/contrast settings through the screen control pannel is cumbersome, that's why I was looking for an alternative, like f.lux, but I was afraid of introducing flicker or something like that because I didn't know how f.lux worked, that's the origin of my question.

    I'm actually trying to resolve a health issue: my right eye is bloated and the upper eyelid is red. I visited a lot of doctors but none could find an explanation. So I'm left looking for other possible explanations. My problem started when I switched from my laptop (and it's tiny 10.4" TFT screen) to a desktop with a large LED screen. But it could just be a coincidence, I've got other health issues that could play a part. Neither the ophtalmologist nor the dermatologist put the blame on the computer screen, maybe they're right but LED technology is relatively new, that's why I'm not discounting it outright. In any case my search has led me to discover f.lux, and just that has been helpful, I've been using it for the past 4 years at least and I now can't imagine myself working on a computer that hasn't f.lux installed.

    If you have multiple health issues, then I sincerely recommend trying these supplements (which are really just superfoods):

    Fermented Cod Liver Oil: http://www.greenpasture.org/public/Products/CodLiverOil/index.cfm

    Fermented Skate Liver Oil: http://www.greenpasture.org/public/Products/SkateLiverOil/index.cfm

    High Vitamin Butter Oil: http://www.greenpasture.org/public/Products/ButterOil/index.cfm

    (or you can just take this: http://www.greenpasture.org/public/Products/InfusedCoconutOil/index.cfm)

    ...and even a new product called CHAMP Pro Plus: http://www.greenpasture.org/public/Products/CHAMPProPlus/index.cfm (I recommend buying it from the website of the product's creator for a much lower shipping cost: http://www.radicalmedicine.com/product/champ-pro/)

    The oils are perhaps the most important thing here, but when I combine the oils with the CHAMP Pro Plus, I have fantastic results. These superfood supplements have a very complimentary effect between each other. I never had any eye problems like you described, but these oils and the CHAMP Pro Plus have helped me do a complete 180-degree turn in my health and go from hating absolutely everything to loving everything (that's the super short microscopic version of the story).

    Due to all the health benefits these superfood supplements provide, I would not be a bit surprised if your "other health issues" were to be completely resolved along with this eye problem being completely resolved as a result of healing all of the "other health issues". Naturally, it can't be an instant fix. It could take days, weeks, or even months (probably just days or weeks for you), but I believe that I am living proof that the monetary cost of these superfood supplements is severely outweighed by the health benefits they provide. They could cost 5x as much and I'd still buy them, and that's all because of my "before and after", and also because of what they do for me on a daily basis. They enable me to love living in my body. They enable me to love life, and to love everything.



  • @Amun-Ra I've got one more idea, what light source are you using in the room your monitor is in? If it's any type of fluorescent I suggest you find either a cool white LED (and get one that is high quality, I can help) or go the opposite route and get a warm white led bulb. For $5 the IKEA Ledare is the best option beating way too many $10 bulbs.


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