I've been experimenting with the cheap spectrometer, and boy is it cheap, as far as I can tell seems to work. Unfortunately, it has shown me nothing useful. All the LED LCD screens have a near identical output of a high blue peak, and lower red and green. The plasma tv I tested was much more balanced.

It did show however, that despite the smartphones being set to what seemed like a similar brightness to desktop monitor, they were infact significantly brighter.

Desktop monitor Benq BL2405, -30% blue light mode enabled

Plasma tv

Old Iphone (not sure which, still had a 4" screen)

IMO Q2 Smartphone

I'm going to try some physical and software overlays later and see how the spectra change.

    Seagull The graphs are rough but still very interesting. Do I understand correctly - you fill the screen with white while measuring ? Also, any OLED phones among the measured ?

        I have said it before - I don't think Blue Light is the problem here. It's definitely not GOOD for you, and it could be a contributing factor, but if it were the problem someone would have come up with a new pigment to use in the Liquid Crystal layer that's better at blocking the bad frequencies.

          Gurm Maybe it's not abundance of the blue light, but lack on the red side of the spectrum, or blue/red ratio.

              cybee Yes, all the screens were displaying white when I captured the spectrum. Unfortunately I don't have any oled devices available to test.

              cybee My thinking also, I will try to balance the spectrum with colour filter overlays and see if my tolerance to them improves.

              Here is a halogen bulb

              It may be possible that new quantum dot screens produce a much more balanced spectrum As they use a variety of coloured LEDs, not just 'white'. If the indicative spectrum shown below is correct Qdot lcds may have a much more plasma like spectrum.

                    Seagull Here is a halogen bulb

                    Looks like a mercury vapour lamp - actually reminds me of the projector UHP lamp spectrum. In Incandescents yellow/orange/red should absolutely dominate. Maybe limitation/inaccuracy of the spectrometer ?

                    Projector UHP bulb spectrum example:
                    Halogen (incandescent):

                    Seagull My thinking also, I will try to balance the spectrum with colour filter overlays and see if my tolerance to them improves.

                    While I'm interested in results of such experiment, I must say that in theory filling the LCD screen with red colour should produce the same results. I personally don't find it tolerable - the full red or green gives the same strain (not sure if less or more). Although maybe external color filter will do better filtering so worth trying. BTW it would be interesting to measure the spectrum of red (and green) screen, would there be detectable blue peak or other pecularities..?

                    Just as we're discussing spectrum part of screens - I disassembled LCD display recently and must say that LCD panel itself is quite opaque even in white (open state) - 60W incandescent lamp barely penetrates it. The LED backlight is extremely bright and has quite unpleasant violetish tint (I almost fell of the chair when accidentally enabled the disassembled screen 🙂). So if there's some parasite spectrum part that is invisible and is not filtered by the LCD panel, there can be enough of it to produce straining effect for sensitive people. But then, something like computer screen glasses should help, as they have UV filter etc., which is not the case for me.

                          cybee It certainly isn't the best, particularly in low light. Plus its not been calibrated in anyway. If I find relief from the colour overlays I may invest in a better spectrometer so as to better understand whats occurring.

                          Tried to get a spectrum of an led screen running flux, but didn't turn out very well. Seemed to crush green, and bring the blue spike down to the level of red at moderate levels.

                            4 days later

                            Well I gave some colour filters a try, but no joy so far. I am somewhat hopeful that the green filter might help a bit when I have a migraine, but it does not appear to be a factor for me. I am going build a pwm detector as described by martin, perhaps that will shed some light.

                            a year later

                            How do blue light filters work? Is it different from me manually decreasing blue levels? I got a new monitor which has a blue light filter. It overrides RGB adjustments when activated. But it is still too blue for me since I'm used to adjusting the blue of my old monitor manually so low that my monitor literally looks yellow. Isn't the blue from the backlight already filtered out when I lower blue setting manually? How should I use my monitor?

                              wohar

                              Unless you are physically attaching something to the screen, they all work the same way, by dimming the blue pixels more than everything else.

                                And by doing so, it seems some of them can introduce temporal dithering, adding additional eye strain. It seems the GPU driver makes this choice for you, and so you could have one machine that is fine but another one that hurts as soon as you enable the filter program. Keep in mind that the habit of turning on a blue light filter on a new device as the first thing you do could make an otherwise perfectly fine device unusable.

                                Same experience on the device itself. However wearing the glasses definitely seems to help. Have a few different pairs/brands and I’m sure it’s better.

                                I bought an "24" EZ pro protector anti blue light shield", a physical shield to be placed in front of the monitor.
                                I still got the same IPS headaches, it hardly helped.
                                I feel much less of the headache on a VA 144hz panel.

                                22 days later

                                Having used a few brands: Felix Gray, Charles Eyewear, Occushield. There is definitely an improvement with Blue light glasses. Really hard to figure out why that works so well but when it's a permanent shield on the laptop not so much? Will try one more brand of this.

                                I've tried several of them and they made no difference to a Macbook pro or Dell laptop that caused me similar problems. I've also tried blue blocking glasses / gunnar glasses and they made no difference 🙁
                                I also use Flux but I dont think it does anything as my 'good' devices are good without it

                                4 months later

                                Have you tried Ocushield ones? For some reason this makes every device totally usable

                                • bkdo replied to this.

                                  Quad43

                                  Did Ocushield really work for you? What devices did you have trouble with before using it?

                                      I've spent literally thousands on custom color tints testing, custom color tinting sheets, custom color tinted lenses, repeated testing, at multiple practitioners who were 100% blue light was the issue. In my case at least it was a complete red herring for screens.

                                      • jen replied to this.
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