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  • soundstar3 Level 1 (0 points)

    Jessiah1, i want to suggest you one thing (probably you already have tried it). Stop using the plasma for one week, there is a small probability (for some unknown reasons) of that screen to give you eye sensitive to other screen thecnology. Then try again a flicker free led monitor.

  • tfouto Level 1 (0 points)

    If you dont understand science, try harder, study more about it. It's not my science by the way, it's everybody science...

     

    http://www.displaymate.com/Spectra_QD.html

     

    Can you see those graphics? For instance the ipad blue line. That's the spectrum for white light. The sum of that spectrum gives white light. As you can see from the ipad graphic, the blue narrow part of the spectrum  (400-500nm) has twice the intensity of energy of red part of spectrum and also almost double the green part. The red and green cover more then the blue which really narrow, but the blue is much more intense. That graphic is white light that the ipad has. This white light is not uniform as opposed to the sun which is almost flat... Almost same intensity for all parts of spectrum.

     

    It's not saying that the blue light of the led it's not the same of sun, but that has nothing to do with what i am saying. Not all whites 'are the same'... The way you combine all colors, spectrum variations, you get different whites...

  • peter_watt Level 3 (910 points)

    If you say so. Good luck with your problem.

  • Dovez Level 1 (0 points)

    tfouto said:

     

    "It's totally diferent, the spectrum of light of a clear sky and a led screen.

     

    Clear light it's a flat spectrum. All the cones of the eye are receiving the same amounts of light. The processing of color in the brain is even.

     

    On a led screen, the light is basically almost blue part of the spectrum at a high energy. The green and red are much lower. The blue cones are the most stimulated. And the problem is that the eye has much less blue cones than green or red. Much, much less. I suppose the blue cones are much more sensitive, or the brain processing the blue is more efective. Maybe the processing of light in brain with such an uneven spectrum of light is problematic for some.

     

    The problem is just not the blue light, it's the totally uneven distribution of light. That's the difference between a clear light and a LED screen. It's the relationship between the amount of total light received by all cones and the blue ones... A world of difference..."

     

    I have to agree with peter_watt here about the uneven spectrum distribution "problem". He's writing from an unbiased point of view. Uneven distribution of light frequencies is called colour. If uneven color distribution was a problem, you couldn't stand looking at red, green, blue or any colors individually. All you would be able to tolerate would be perfect white full-spectrum light, which also contains blue. If your screen doesn't even come close to looking blue, this means it has an extremely lower percentage of blue in its spectrum then the blue sky, which is extremely blue and extremely bright.

  • mojarvinen Level 1 (0 points)

    I can see the problem of the blue light being uneven. Red and Green can aloso be uneven,. But if Blue is the problem, coudl blue filtering glasses with F.lux and maybe throwing sunglasses on top, create a situation where the blue spike is completely removed and all other clours are also move even, as the whole level of light is so much lower that it is hard to say diffrentiate it from, say looking at a paintin that is dimly lit.

     

    That way one coul be sure that if blue is the problem, then there is hope that when manufacturers make a solution that makes the light spectrum more even, also your eye irritation disappears.

     

    I personally tried to use the flickering displays with blue blocking glassses and f-lux installed and set to the maximum yellowness, but that made absolutely  no difference. I've also tried wiht with dark sunglasses. Only removing the flicker, removes my eye irritation.

  • tfouto Level 1 (0 points)

    mojarvinen,

     

    Your problem dont have to do with blue-light, so using blue-blockers dont to a thing...

     

    Flicker/dithering is the main cause.

     

    Dovez,

     

    I am tired of repeating myself, really. If you dont grasp the concept, i cant repeat myself to death.

     

    It has to do with mixing of  coloures. Sun white, is even... The brain processes normally the white. On those Led screens, dont... The brain is processing whites and mixtures of colours on a non-natural way, which is used for millions of years. There are physicians who said this.

     

    Why kindle paperwhite front-light causes me hard pain at full brightness? Dithering, flicker? Of course not...


    And why flux, solves the problem to me on led displays?

     

    It's not blue alone. The problem here is the brain is processing the mixture of colours especially white, with an uneven spectrum intensity of light. It's a theory, i might be wrong, i might be right, who knows. But it's not blue light alone...

  • Dovez Level 1 (0 points)

    Let's say a person has a problem with a monitor. Irritated eyes are the problem. Just think about if this explanation makes sense:

     

    Let's imagine your light stress tolerance level is at 50 (which would mean you can tolerate all light stress up to 50 points). Let's imagine 45 points of stress is caused by invisible flicker and 10 is caused by a bit excessive presense of blue light in the spectrum. together we have 55 and the person gets irritated eyes because of too much light stress. Imagine the person uses flux and reduces 70-90% of blue. The light stress level is under 50 again and the person says he has no problem. He then claims blue light was the problem. But what if the flicker was removed? I think the blue dominance wouldn't play a role.

     

    Let's imagine you have a different tolerance level. 30, for example. You still have 45 poins of flicker light stress and 10 of blue stress. Here removing blue doesn't make a difference, but removing flicker makes a diffeerence for everyone.

     

    If this is correct, then removing all kinds of flicker would serve as a universal solution and removing blue would be only helpful for some.

  • Dovez Level 1 (0 points)

    tfouto wrote:

     

     

     

    Why kindle paperwhite front-light causes me hard pain at full brightness? Dithering, flicker? Of course not...

     


    Why do you keep giving special importance to it being on full brightness? Do you think it doesn't flicker at full brightness? Have you measured it with a reliable instrument? Please repeat it if you have mentioned it here before.

  • Dovez Level 1 (0 points)

    tfouto wrote:

     

    The problem here is the brain is processing the mixture of colours especially white, with an uneven spectrum intensity of light. It's a theory, i might be wrong, i might be right, who knows. But it's not blue light alone...

    Don't you think using flux creates an unnatural uneven spectrum of light? I mean how is it natural when everything is red?

  • tfouto Level 1 (0 points)

    I will.

     

    But PWM is no problem to me. I have 2 monitors with pwm, and dont have any trouble with that...

  • Jessiah1 Level 1 (0 points)

    soundstar3

     

    "Jessiah1, i want to suggest you one thing (probably you already have tried it). Stop using the plasma for one week, there is a small probability (for some unknown reasons) of that screen to give you eye sensitive to other screen technology. Then try a flicker free led monitor."

     

    Interesting, I have never heard of this theory, can you tell me more about where it originated? As for testing it I certainly would not need to as I have spent weeks away from this monitor with no effect to my other sensitivities.

     

    Based on the back and forth I see from last night I feel like both sides of the argument have interesting points and no one is completely incorrect necessarily. I say this because no one here is a physicist and therefore theory's are just that and nothing more, good discussion thoughAllow me to add my own, haha!

     

    The sun is a more even spectrum of light than any other source, even incandescent light bulbs, it also has the highest amount of blue light however it travels through many filters before it reaches our eye's.

     

    Other sources of light like LED lighting are not filtered the same way and in addition to this they can deliver light in broken waves, flicker of light typed out would look something like this: - - - - - - - - - - -

     

    So if you imagine a light source with uneven light spectrum that our eye's are not accustomed to viewing being delivered with flicker you have the worst possible case scenario, thus it bothers everyone. If removing one aspect of this scenario helps you it does not mean the other is simply tolerable for you by default, it means you improved the delivery of light to your eye's in a direction that makes it tolerable.

     

    I think Peter has some experience with light that helps provide some educated feedback on this subject, otherwise I cannot tell who else here has an educational background in the Physics of light? I will be back here with more factual data when I have taken this further with some PHD's and hopefully the Boston Photonics lab. We all need some more scientific explanation in order to move our theories forward from here IMO.

     

    Respectfully,

     

    Jesse

  • soundstar3 Level 1 (0 points)

    This theory came from my own battle with screens for more than 5 months. My next test will be with a rubylith film filter that is usually used by astronomers.  Most astronomical programs have a "red light" or "night vision mode". The screen will lose image quality, but im just looking for a comfortable way to use a screen.

     

    There is other thing i would like to test, but couldn't find a way to do it. With flux it is possible to change the color temperature during a 24h period, what im looking for is a program that can change color temperature during 1 minute period, so it goes to maximum and minimum in each minute. There is a small probability of this to work for some persons. Why? Because when many persons change color temperature (or monitor or operation system) the eyes feel better for some time (minutes/hours/days). I think the eyes are more sensitive using same color temperature all the time, so if it changes every 1 minute (it could be more), the eyes will not feel saturate, and maybe for some it will solve the eye strain. Would like to find a way to change flux code, for a customizable perido (less than 24h).

     

    Hope it helps and sorry about my poor english.

     

    Edit: It's possible to test this idea without a program. I will set an alarm for every 3 minutes where i will change manually color temperature with flux. I will set an interval from 3500k to 6500k, and every 3m will increase/decrease 300k. For some persons flux work and i think if it goes to maximum and minimum more times a day it will also work with more persons.

  • Jessiah1 Level 1 (0 points)

    Very interesting test, our natural lighting changes during the day constantly, I am curious how this test turns out. Being that F.Lux only helps me in a minor way I do not think it will solve my issues but still an interesting idea.

     

    Jesse

  • tfouto Level 1 (0 points)

    I measured the kindle paperwhite at several levels of brightness with a photodiode, and it has no PWM.

  • Dovez Level 1 (0 points)

    Thanks for measuring. I remember somebody here had a problem looking at a certain e-ink reader even without a frontlight, though he did not have trouble with previous e-ink readers. The most plausible explanation then was the new spatial dithering or however it's called. It's not the kind of dithering that results in flicker, but rather in patterns. The dithering is used to create the illusion that there are more shades of grey. I'm not saying this is your problem, but there is a small chance it is. If you are curious, research it more and tell us about your findings! Another idea: why not find somebody who repairs electronics and ask him to remove the frontlight? If it truly is the frontlight's fault, then you would have a usable device after this procedure... and you could be absolutely sure if it's the flicker-free frontlight's fault or not.