Well. This is interesting.
I have done some research on light and sound frequency effects on cells etc. There is a ton to be found online. Now you got me thinking again. Oh boy.

Actually blue light has been known to be carcinogenic and affect sleeping for many years already. This is the same reason why Samsung, Apple, and others have added a Blue Light Filter feature to their phones that makes the colors warmer (less cool/blue) so it causes less harm to your eyes, health, and ability to sleep. There’s also a popular program for your PC called f.lux that makes the colors warmer at night time and colder in the day time, which I installed on my PC. It works great.

That’s why for me I only use 4000k or lower for my night time EDCs.

so imagine a LEO and he is using a CW light for Duty at night. does this matter too?
thanks.

In standarized world there is a term: photobiological safety. Light can have many effects on human body. strenght, wavelenght, PWMs – these all take effect on us.

thanks so I am wondering then if it just best to take cool white out of equation when on duty at night and use neutral warm .
?.
cheers…

1stein wrote:

In standarized world there is a term: photobiological safety. Light can have many effects on human body. strenght, wavelenght, PWMs – these all take effect on us.

optosolis wrote:

thanks so I am wondering then if it just best to take cool white out of equation when on duty at night and use neutral warm .
?.
cheers…

1stein wrote:

In standarized world there is a term: photobiological safety. Light can have many effects on human body. strenght, wavelenght, PWMs – these all take effect on us.

Man, I wish my knowledge allow me to give you the right answer. But it does not and since we’re talking about human safety (safety always 1st) I do not dare to answer. But I’m nearly sure some requirements (made upon research) are given in occupational hearth and safety guidelines. (OSHA?)

SKV89 wrote:

There’s also a popular program for your PC called f.lux that makes the colors warmer at night time and colder in the day time, which I installed on my PC. It works great.

I thought windows 10 already came stock with the night light filter feature? Pretty much never used them as I kinda sleep early anyway

sorry that has to be bogus.

Hmmmm…so even if color temp is lower, is it possible for hidden blue to be in there?

there is blue light in sunlight… is that causing all these symptoms?

wle

Hmmmm….. I do not pretend to understand either side of this. But it seems not all Blue Light is bad??

Blue-light therapy warding off skin cancer

Blue Light Therapy: Uses and Side Effects – Healthline

My understanding is that blue light specifically is the type of light that impacts the sleep cycle, as opposed to red or green. And for this reason, warmer/cooler CCT lights have different effects. I've easily observed this in my own life: one room of my house has 2700K lighting, and I will fall asleep if I try to read a book in that room. The other areas of my home have 4000K to 5000K lighting, and I have no issues reading and staying awake there. 

Anyway, this becomes an issue when significant blue-light invades spaces where it hasn't always been. Cool-CCT streetlights in particular could be an issue, as they shine at night. If people aren't aware of the impacts of blue light on their sleep schedules and/or don't accommodate for that impact in their life, they'll have sleep cycle disruptions. This can range anywhere from decreased quality of sleep to straight-up insomnia. In fact, I had seen studies showing this impact comparing dark vs. brightly lit neighborhoods already (wish I still had that source), and I'm not surprised at all that adding more blue light would strengthen the effect.

My answer is to move into my warmly lit room at the end of the day and wind down there. Also to limit screen usage and/or blue-light filter the screen. And lastly, blackout curtains

TL;DR: It's long been known that light affects sleep, more blue spectrum means stronger impact, and sleep impacts everything else

so how long is the effect supposed to last?

how strong and how blue does it have to be, to remove X minutes of sleep?

wle

The liberal use of the word “may” negates the declaration of a scientific conclusion. H2O “may” be lethal… Circumstances dictate how lethal.

optosolis wrote:

so imagine a LEO and he is using a CW light for Duty at night. does this matter too? thanks.

It’s like a magic cancer-wand. Point it at a bad guy and bam! Dude dies of cancer, and doesn’t even get to die in his sleep. Teaches him right for lurking around an alley in the dark.

I knew there was a reason why I kept all those crappy LED maglites.

I thought using a cool white for not so long on and off during a night duty LEO shift would be ok as It wasn’t excessive.
not sure, maybe best stick to NW/ Warm

For those concerned and using firefox, opera or chrome without a built in color temp changer, this add on is very handy. It’s not automatic, but just leaving it on all the time isn’t that bad either.
https://mybrowseraddon.com/screen-color-temperature.html

Quote:

the “blue light” emitted by the LEDs may be disrupting the body’s circadian rhythm, which in turn affects hormone levels. Both breast and prostate cancers are hormone-related.

The quotes from the article seem to answer a lot of the questions here. The issue is constant, bright, high-CCT street lighting being linked to changes in sleep patterns/hormones.

Maybe I’ll show you some example – from photobiological safety point of view.

The main issue here is a blue light spike at 430-440nm – it’s caused by a phosphor coating quality and phosphor’s mix.

As you can see not only CCT matters, the 4000K cannot be named “safe” or “safer” sorry SKV89 ;).

I would think it’s a combination of factors that link this all together. IMO it’s mostly to do with ones lifestyle. If you’re up late regularly chances are you could be in the presence of bright light which further interrupts the sleep cycle.

http://www.center4research.org/women-work-night-shifts-higher-risk-devel...

At the bottom of the first paragraph “Researchers found that night shift work links to breast cancer because it can change a person’s sleep-wake cycle. This has a lot to do with artificial light.”

wle wrote:

so how long is the effect supposed to last?

how strong and how blue does it have to be, to remove X minutes of sleep?

wle

AsI recall, it takes only a brief exposure — think incandescent white nightlight bulb — to suppress melatonin production. Then it takes half an hour to an hour for the body to resume produccing melatonin. It’s the melatonin that suppresses breast cancer (which is why night shift workers and people in areas newly supplied with nighttime electricity show an increase)

https://www.google.com/search?client=firefox-b-1-d&channel=tus&q=melaton...

https://www.health.harvard.edu/staying-healthy/blue-light-has-a-dark-side

You can buy a spectrometer kit (several variations, varying prices) from PublicLab.
https://store.publiclab.org/collections/bulk/products/lego-spectrometer-...

EDIT
Here’s the spectrum from one of the claimed low-blue-light 110v bulbs

See http://budgetlightforum.com/comment/1528412#comment-1528412 from DominikM for spectra

I used my kit spectrometer to check the claims of bluelight suppression. A lot of it is hype — f.lux for example changes the apparent color temperature by adding more red, rather than removing blue. The spectrometer shows plenty of blue light still being emitted from the computer screen (whether fluorescent or LED lit).

I swapped amber LEDs into half our home flashlights, for nighttime use, and for room lighting we use amber LED bulbs or “bug light” compact fluorescents for evening light during the short-day half of the year.

Doing that cured our insomnia, which had gotten bad when we replaced all our incandescents with “white” compact fluorescents some years ago.

DominikM wrote:

Maybe I’ll show you some example – from photobiological safety point of view.

The main issue here is a blue light spike at 430-440nm – it’s caused by a phosphor coating quality and phosphor’s mix.

As you can see not only CCT matters, the 4000K cannot be named “safe” or “safer” sorry SKV89 ;).

I think CCT is actually still a huge part of what’s happening there. Even 2700K light from a blackbody source will have far less of the blue end of the spectrum compared to 4000K.

wle wrote:

so how long is the effect supposed to last?

how strong and how blue does it have to be, to remove X minutes of sleep?

wle

https://curiosity.com/topics/this-is-how-little-blue-light-it-takes-to-d...

has several links including this one: https://www.lrc.rpi.edu/resources/newsroom/pdf/2010/CircadianLight_8511.pdf

Quote:

A pure blue LED light only takes 9 lux to suppress melatonin secretion by 25 percent.

Yep.
It’s what matters.

4000k is better, 3000k is even better, 2700k is even better than 3000k, and 2000-2200k has almost no blue light.

I’d love to test 1800k LEDs myself.

Could someone use Luminus 3030 Cubes in Virence’s large MCPCB?

“Photobiologically safe: exempted from bluelight hazard” sounds like marketing hype to me.
But apparently it’s referring to a European regulation.

Quote:

LED-based products must meet photobiological safety standards: part 2 (MAGAZINE)

The potentially complex procedure of evaluating LED photobiological safety is now a legal requirement in Europe, but few countries have yet followed the European mandatory-testing lead. LESLIE LYONS discusses the implementation of the IEC62471 standard after an in-depth look at the measurement of radiance and irradiance.

Quote:

The potential hazards of exposure to the skin, the front surfaces of the eye (cornea, conjunctiva and lens) and the retina are evaluated through consideration of six specific hazards with respect to exposure limits (ELs) provided for an exposure duration of eight hours, taken as a working day. The standard does not consider the potential effects of long-term exposure, nor of abnormal photosensitivity.

In the case of hazards to the skin and front surfaces of the eye, it is sufficient to take into account the amount of light incident on the surface in question. However, to consider hazards to the retina, one must take account of the imaging properties of the eye. It follows that two distinct measurements are required: irradiance and radiance.

The “blue light hazard”
https://www.google.com/search?client=firefox-b-1-d&channel=tus&q=%E2%80%... is damage to the eye, perhaps the claim is this emitter is not strong enough for that problem to arise.

https://www.google.com/search?client=firefox-b-1-d&channel=tus&q=Photobi...

A few years ago I corresponded with one of the researchers in the field, who said that at a European scientific conference on the subject they were already seeing industry PR people there to deny any possible problem with the blue-white LEDs their companies were pushing as “so cheap they pay for themselves in saved electricity costs” —- too cheap to meter, basically.

hank wrote:

“Photobiologically safe: exempted from bluelight hazard” sounds like marketing hype to me.

https://www.ncbi.nlm.nih.gov/pubmed/24487866

Opt Lett. 2014 Feb 1;39(3):563-6. doi: 10.1364/OL.39.000563.
Phosphor-converted LEDs with low circadian action for outdoor lighting.

https://www.ncbi.nlm.nih.gov/pubmed/21600300

Quote:

Prog Retin Eye Res. 2011 Jul;30(4):239-57. doi: 10.1016/j.preteyeres.2011.04.002. Epub 2011 May 14.
Light-emitting diodes (LED) for domestic lighting: any risks for the eye?
Behar-Cohen F1, Martinsons C, Viénot F, Zissis G, Barlier-Salsi A, Cesarini JP, Enouf O, Garcia M, Picaud S, Attia D.
Author information
Abstract

Light-emitting diodes (LEDs) are taking an increasing place in the market of domestic lighting because they produce light with low energy consumption. In the EU, by 2016, no traditional incandescent light sources will be available and LEDs may become the major domestic light sources.

Due to specific spectral and energetic characteristics of white LEDs as compared to other domestic light sources, some concerns have been raised regarding their safety for human health and particularly potential harmful risks for the eye.

To conduct a health risk assessment on systems using LEDs, the French Agency for Food, Environmental and Occupational Health & Safety (ANSES), a public body reporting to the French Ministers for ecology, for health and for employment, has organized a task group. This group consisted physicists, lighting and metrology specialists, retinal biologist and ophthalmologist who have worked together for a year.

Part of this work has comprised the evaluation of group risks of different white LEDs commercialized on the French market, according to the standards and found that some of these lights belonged to the group risk 1 or 2. This paper gives a comprehensive analysis of the potential risks of white LEDs, taking into account pre-clinical knowledge as well as epidemiologic studies and reports the French Agency’s recommendations to avoid potential retinal hazards.

This is the main reason I want most of my flashlights in 2000K or below. Blue light affects my sleep at night, so keeping my flashlights at 2000K won’t give me any melatonin suppression. All my lights in the house are halogen and i cover up all sources of LEDs with red or black tape. 2000K is a little spooky sometimes though since the color temp looks like a candle flame, so i have a bunch of 2700K flashlights on hand too… just an excuse for more flashlights.