Librem 5 Backlight PWM frequency

I’ll buy it when librem phone comes with e-ink screen. This will be a perfect phone.

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I suffer from migraines and use that on debian. Specifically, I use

xrandr --output VGA1 --brightness .5

where the number (I’ve got it set to half hence the “.”) is the global brightness setting so just mess around with it till you find something you’re most comfortable with.

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As well, Debian 10 offers new messing around within Settings/Devices/Displays and it is called: Night Light with Schedule and Color Temperature. Going from around 6000 Kelvin down to around 2000 Kelvin helps to some a lot, in short, without discussing the blue light dark side. I am very thankful to Debian on Wayland for this feature! But don’t expect that yours display Red color (No.9) quality will be more red as it depends on initial technology used (easily might be less than 50%). For those interested, here is link to the currently best Color Rendering Index (from LED technology for general use, not for backlights in LCDs) just for comparison (even though real display data are not commonly available especially if they don’t offer 10-Bit video output/true 30-Bit color output) and reference.

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will never happen. the software costs of developing that isn’t worth the 5 people who will buy it

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I’m nocturnal, but that sounds really cool for people with day jobs in respects to protecting their circadian rhythms :slight_smile:

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don’t use that if you can afford not to … just use an external monitor with built in hardware OSD profiles for Reading and switch to sRGB when you need color fidelity.

or better yet (if you can afford it) buy a hardware color calibration device and use displayCAL under X (wayland needs more love with this to work without error)

a little old but will update when wayland is resolved …

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Yes, you can look at my thoughts just another way around: LCD screens between 6500–9300 K + minimal PWM frequencies response times of around 250 Hz gives us just right formula not to sleep at all for several hours after done with our homework late at night (but some young people still need to keep up with their circadian rhythm as scheduled, very next morning). Lower brightness might help of course, yet not with low PWM number, afaik. Anyway, I would rather, after sunset, look at something with no-PWM (or higher then 20000 Hz), even if this mean full brightness, and 2600 K instead. I’ll leave at this just not to go way out of topic, but interested in this conversion to lower Kelvin numbers may take a look at “The values as a handy python dictionary” from Andreas Sieß and adjustments made on his photo Grand Traversata Delle Alpi.

Yes, please! And this play around with Kelvin adjustment on wayland was actually for reading usage.

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or if you have 2700k classic light bulbs or LEDs with that color temperature … if you are keen to do ambient light white-point matching … contrast will suffer …

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@Quarnero
Ah, this explains why the only viable bedtime reading is strictly traditional book for me and why on bad days the lighting in the new subways will trigger a migraine but never the older cars. Hey, to you, patch, and everyone else posting here…thanks because this is rather interesting. I’m only barely comprehending it (and only because I used to date a DOP years ago who would go on about colour temperature, etc. as it relates to film) but it is intriguing.

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+1 but sometimes the internet is just too much …

That’s why, because of better contrast, I use Cobalt option (instead of Oblivion) on my gedit. I just wonder how would look option with some reddish font on the same black. And, “ambient light white-point matching” will not make my writing here better anyway.

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I’m (kind of) sorry but I disagree :wink:, as I’m sure you already knew (even if just subconsciously aware) that something has changed, but it was not you that changed. And, IMO, you are right on topic here. Older cars use tungsten halogen headlamps and as your eyes understand (see) difference they silently argue (migraine) or make some kind of protest when not pleased, against blue LED light “bites” that are usually well combined with harmful PWM glimmer. I would rather say that exactly this, noticing the difference between harmless looking at static pictures, like books you read or paintings you admire and the looking by exposure to the blue LED light combined with the poor PWM frequency, makes you expert on this field (because most of us don’t have quality “time” to notice this, and get the most expensive blue-light blocking glasses against such, but such glasses cannot improve bad cause/source and particularly not glimmer). Therefore just two advantages I currently think of about tungsten filament light bulbs as healthier option for our eyes:

  1. Color rendering index (CRI or Ra) of light was (because incandescent lamps are almost past time) 100%, same like our daily sunlight, without any glimmer which means zero or 0% of PWM (was not in use),
  2. Out of topic, but color temperature was up to 3000K and this was for decades purposely mandatory for night traffic (even though that the quantity of light (lux) was relatively small, in comparison with LED, but sufficient), until the blue LED was invented and awarded with Nobel Prize in Physics.

P.S. I might try to get OSRAM 2600K Fog Breaker Series light bulbs (I had some similar earlier) for my car because they are worth every cent when needed. It is just funny (to me) how some of the most expensive SUVs (homologation inclusive within EU) cannot drive more than 50 km/hour on country roads when fog is heavy, but who cares, mass production case. Let me make up why it is like this (the reason why): because they drive main LED headlights with color that is often more as 5000K and fog just returns white light like mirror. Topic borderline shows barely to me but I know is there (Am I still on the road? I see just fog and nothing else.).

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here are some LED modules that are 98 CRI but very expensive > https://store.yujiintl.com/collections/high-cri-led-module check the about page also …

led is energy efficient and it has that going for it … sure there are the ones that are really high powered but the luminous flux emitted is much higher compared to traditional lightning methods …

about glasses … my pair have anti-blue light treatment and they DO affect the perception of blue-light coming from the display-panel. it’s not an assumption i can very clearly see with my OWN eyes a DIFFERENCE by taking them on and off. This is funny because my ophthalmologist (link for younger audience - if there are any :stuck_out_tongue: ) said when i asked that it will NOT change my color perception. i suppose it’s pointless asking ( if it IS a filter it will change SOMETHING at least)

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me too. but then again i’ve always found out vim or emacs to be preferable in terms of customisation :wink: (probably too much for just reading lol)

imo the darkest sepia color background with very light orange text - that any color monitor can correctly display - is the best choice in terms of contrast/eye-fatigue

true OLED would be nice to have on any Librem device but without the burn-in and the power consumption :stuck_out_tongue:

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Thanks! Your link to Beijing Yuji International Co., Ltd., my link above to Toshiba Materials Co., Ltd. TRI-R and this one to Seoul Semiconductor SunLike LED are links to the very same products. I’m currently using this light bulb from Yuji with 3000K.
Edit: https://www.yujiintl.com is manufacturer page (without store.).

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25,00 € tax excl. for that bulb seems acceptable to me if you compare to other similar price but not the same CRI specs. 10w for aprox 900 lumen is a little steep but it’s ok. but enough about Yuji LEDs - getting to far off-topic here …

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I think anyone who waits for the bus (never learned to drive, sad I know) at night can be considered an expert :frowning: Not only do you get assaulted by those insane xenon or whatever lights but also those flashy pulsing bicycle lights (which I actually agree with for cyclists safety, but they’re still way annoying!) The best solutions I’ve found so far is : always wear a baseball cap so I can lower my head and I too have to special coating on my glasses. That’s what helps a bit for real life, but for looking at a phone (which is more controlled) I wonder if there is a way to cancel out the glimmer (or at least change the Hz (?)) to something more reasonable by maybe adding to it somehow? (kinda like how white noise works?)

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As earlier stated from @dcz this is what we expect, nothing more and nothing less:

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That’s great news :slight_smile: …annnnd I probably should have been paying closer attention :hushed: Ah well, I had a lovely Saturday because wondering about it led me to contemplate the old Battlestar Galactica viper helmets and then guess what I did today :smiley:

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