And because blue light is a next-of-kin to UV light, keep your pants on when hunting for scorpions at night.
So, what do we actually take away from all this??
- 1. Blue Light DOES NOT cause cancer.
………a. It does/can affect sleep patterns, which in turn affects Melatonin/hormone production; which may make us more prone to develope certain type cancers.
- 2. Is this cause for mass hysteria & wide scale panic??
……….a. NO
- 3. What can we do to possibly avoid this potential ‘Blue Light Death Trap Phenomenon’?? [‘BLDTP’ for short….
]
Well, without getting overly crazy about it; we can do the common sense things sbslider, pinkpanda3310, & a few others have mentioned:
…………. a. Limit computer, phone, & screened device use a couple of hours before bed.
…………. b. Have a fairly routine sleep time in a dark place. A very faint night light will not hurt…. even if it is Blue most likely.
…………. c.’Don’t Worry, Be Happy’……
The article below from Harvard Medical School is interesting.
Harvard Health Publishing
Harvard Medical School
Harvard Health Letter
Blue light has a dark side
What is blue light? The effect blue light has on your sleep and more.
Updated: August 13, 2018 ……. Published: May, 2012
Although it is environmentally friendly, blue light can affect your sleep and potentially cause disease. Until the advent of artificial lighting, the sun was the major source of lighting, and people spent their evenings in (relative) darkness. Now, in much of the world, evenings are illuminated, and we take our easy access to all those lumens pretty much for granted.
But we may be paying a price for basking in all that light. At night, light throws the body’s biological clock—the circadian rhythm—out of whack. Sleep suffers. Worse, research shows that it may contribute to the causation of cancer, diabetes, heart disease, and obesity.
What is blue light?
Not all colors of light have the same effect. Blue wavelengths—which are beneficial during daylight hours because they boost attention, reaction times, and mood—seem to be the most disruptive at night. And the proliferation of electronics with screens, as well as energy-efficient lighting, is increasing our exposure to blue wavelengths, especially after sundown.
Light and sleep
Everyone has slightly different circadian rhythms, but the average length is 24 and one-quarter hours. The circadian rhythm of people who stay up late is slightly longer, while the rhythms of earlier birds fall short of 24 hours. Dr. Charles Czeisler of Harvard Medical School showed, in 1981, that daylight keeps a person’s internal clock aligned with the environment.
Is nighttime light exposure bad?
Some studies suggest a link between exposure to light at night, such as working the night shift, to some types of cancer, diabetes, heart disease, and obesity. That’s not proof that nighttime light exposure causes these conditions; nor is it clear why it could be bad for us. But we do know that exposure to light suppresses the secretion of melatonin, a hormone that influences circadian rhythms, and there’s some experimental evidence (it’s very preliminary) that lower melatonin levels might explain the association with cancer.
A Harvard study shed a little bit of light on the possible connection to diabetes and possibly obesity. The researchers put 10 people on a schedule that gradually shifted the timing of their circadian rhythms. Their blood sugar levels increased, throwing them into a prediabetic state, and levels of leptin, a hormone that leaves people feeling full after a meal, went down.
Even dim light can interfere with a person’s circadian rhythm and melatonin secretion. A mere eight lux—a level of brightness exceeded by most table lamps and about twice that of a night light—has an effect, notes Stephen Lockley, a Harvard sleep researcher. Light at night is part of the reason so many people don’t get enough sleep, says Lockley, and researchers have linked short sleep to increased risk for depression, as well as diabetes and cardiovascular problems.
Effects of blue light and sleep
While light of any kind can suppress the secretion of melatonin, blue light at night does so more powerfully. Harvard researchers and their colleagues conducted an experiment comparing the effects of 6.5 hours of exposure to blue light to exposure to green light of comparable brightness. The blue light suppressed melatonin for about twice as long as the green light and shifted circadian rhythms by twice as much (3 hours vs. 1.5 hours).
In another study of blue light, researchers at the University of Toronto compared the melatonin levels of people exposed to bright indoor light who were wearing blue-light–blocking goggles to people exposed to regular dim light without wearing goggles. The fact that the levels of the hormone were about the same in the two groups strengthens the hypothesis that blue light is a potent suppressor of melatonin. It also suggests that shift workers and night owls could perhaps protect themselves if they wore eyewear that blocks blue light. Inexpensive sunglasses with orange-tinted lenses block blue light, but they also block other colors, so they’re not suitable for use indoors at night. Glasses that block out only blue light can cost up to $80.
LED blue light exposure
If blue light does have adverse health effects, then environmental concerns, and the quest for energy-efficient lighting, could be at odds with personal health. Those curlicue compact fluorescent lightbulbs and LED lights are much more energy-efficient than the old-fashioned incandescent lightbulbs we grew up with. But they also tend to produce more blue light.
The physics of fluorescent lights can’t be changed, but coatings inside the bulbs can be so they produce a warmer, less blue light. LED lights are more efficient than fluorescent lights, but they also produce a fair amount of light in the blue spectrum. Richard Hansler, a light researcher at John Carroll University in Cleveland, notes that ordinary incandescent lights also produce some blue light, although less than most fluorescent lightbulbs.
Protect yourself from blue light at night
Use dim red lights for night lights. Red light has the least power to shift circadian rhythm and suppress melatonin.
Avoid looking at bright screens beginning two to three hours before bed.
If you work a night shift or use a lot of electronic devices at night, consider wearing blue-blocking glasses or installing an app that filters the blue/green wavelength at night.
Expose yourself to lots of bright light during the day, which will boost your ability to sleep at night, as well as your mood and alertness during daylight.
The study accounts for various risk factors by using self reported data from a 52 page questionnaire. You should know that the bias from that data set makes this study flawed. The shear number of studies that have had the hypothesis disproven because of self reported data is mind boggling. I will leave it at that.
+100
Yes, forget about science news articles. They misreport what the studies conclude just as often as they get it right. They’re far more interested in clicks than they are interested in accurate reporting.
Go directly to the study. Make sure it is published in a well-respected peer-reviewed journal. Anything else is junk, and likely just a company doing fake studies just to sell you stuff.
Ideally, find a study that has been replicated, which helps eliminate p-hacking effects. A single study on its own, often later turns out to be false. And beware that statistically significant does not necessary mean it has a meaningful effect.
Wait… it doesn’t??
I’m finding this thread interferes with my sleep.
Warm white gang, RISE UP
Yea I no longer use 4000K for my night time EDC. After over a year of experimenting with different night time lights before sleep and its effect on how easy it is for me to fall asleep, I’m now using only 2700K and under. When I started using the E21A 2500K mixed tint as a ceiling bounce lamp, I started actually falling asleep while watching TV! Previously with my higher temp lights (brighter though) I don’t get sleepy and it takes me longer to fall asleep. 4000K and cooler lights also help me stay awake at night so I like them in the day time.
[quote=jon_slider]
In general, warmer color temps emit less blue wavelength versus cooler color temps. Also high CRI and R9 lights in general, to a lesser extent, emits less blue wavelength because the thicker phosphor converts more of the base blue light into other wavelengths to create warmer and higher CRI light, which allows less blue light to escape unconverted. The blue wavelengths that did not get converted through the phosphor are the “potentially” health concerning portion of the light.
For example, comparing 4000K XP-L HI 70CRI vs 4000K SST-20 95CRI, the XP-L HI produces (visually estimated from spectral graph) 20% more blue light with a much taller blue peak. I have been doing a lot of testing with my spectrometer lately so the above generalization is true for “most” cases however I find sometimes HI CRI of same CCT can produce more blue light than lower CRI of the same CCT. Also I’ve seen lights measuring the same color temp and similar CRI can vary significantly in the amount of blue intensity. So without testing the specific emitter, the above generalization is not an absolute rule.
I’m glad somebody is paying attention to the science.
Chronobiol Int. 2012 Jun;29(5):641-9. doi: 10.3109/07420528.2012.675850.
Assessment of a new dynamic light regimen in a nuclear power control room without windows on quickly rotating shiftworkers—effects on health, wakefulness, and circadian alignment: a pilot study.
Keeping nuclear power plant night shift operators alert — it’s a good idea.
Who designed the original windowless dimly lit control room?
The American Optometric Association has also commented on the above-mentioned Spanish study:
And on other research on the direct photochemistry (this is energy delivered by the high energy blue photons directly to the retina, unrelated to the melatonin/cancer issue)
https://www.aoa.org/news/clinical-eye-care/blue-light-transforms-molecules-
I noticed my eye doctor no longer uses a blue examination light for a long period of time when looking at my retinas, instead they use a yellow light that briefly changes to blue. I read of a couple of cases of blindness where a blue examining light was mistakenly left on too long.
More research https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5854379/
PLoS One. 2018; 13(3): e0194218.
Published online 2018 Mar 15. doi: 10.1371/journal.pone.0194218
PMCID: PMC5854379
PMID: 29543853
Removal of the blue component of light significantly decreases retinal damage after high intensity exposure
Int J Ophthalmol. 2018; 11(12): 1999–2003.
Published online 2018 Dec 18. doi: 10.18240/ijo.2018.12.20
PMCID: PMC6288536
PMID: 30588436
Research progress about the effect and prevention of blue light on eyes
Maybe The Seoul Sunlike (mid power) LED might interest you.
LOL!
thanks for your contributions 
.
very helpful, thanks
so, do you have any quantifyable blue light levels data for
an Incandescent, and the
sw45k N219b 9080, and the
sw35 9080, and the
E21a 3000k, and the
Optisolis 6500k (I expect this one is best used as a worklight, when staying awake is desireable)
fwiw, my computer and iPhone have NightShift enabled, and my house lights are incandescent
bob_mcbob tested the Nichia 219B in a FW3A, if you look at his TM-30 tests you will see that it has a blue spike.
You will find the spectral power distribution of the E21A 3000K and optisolis 6500K on clemence’s website or here for the E21A and here for the optisolis (see imgur link in the message). The 6500K has a lot of blue which is not surprising since it is made to be as close as possible as the reference (D65 standard) which is daylight (above BBL).
thank you
since the N219b is rated for no blue light hazard, the presence of a blue spike is not sufficient info
Im looking for reference number values,
so we can begin to have a conversation about
How Much blue light is being produced
as pinkpanda pointed out, the amount of blue light from a blue tritium for example, may or may not have enough output to impact melatonin and suppress sleep, I do not know
I need numbers… like
X blue units from a N219b is Not capable of suppressing melatonin
while
Y blue units from a cool white fluoro IS capable of suppressing melatonin
etc
numbers so I can compare the relative blue outputs, and numbers that tell me a threshhold value for the “no Blue Light Hazard” designation
I see what point you’re trying to make, but ‘directly causally linked to’ doesn’t make any sense, so that’s not what the article is saying
I don’t know how one could segregate blue light from a given light source and calculate the levels of effect? Especially when “light of any kind can suppress the secretion of melatonin”. Imagine slowly turning on one of your rrt-01 lights. At which point does the light have an affect?
If the study that teacher linked was correct - “Even dim light can interfere with a person’s circadian rhythm and melatonin secretion. A mere eight lux —a level of brightness exceeded by most table lamps and about twice that of a night light—has an effect” Then what?? Lower the light level by a quarter of a lux and you’re golden right :innocent: YehNO , as always life is messier than that.
This discussion is like saying don’t eat hamburger and chips because it’s unhealthy. If it was the only thing you ate then yes unhealthy. If it was mixed in with a regular half healthy diet then you couldn’t pin point that as being the major factor for being overweight. More likely the lack of exercise is the reason which totally gets ignored because it’s too hard.
I understand some people like to go over the science of it all but really, who is going to change their lifestyle because of the Blue Light Fear . Turn the house lights down dim in the evenings and don’t look at screens 2-3hrs before sleep.
EDIT- Looking at my last sentence makes me wonder if that has anything to do with the world population growth rate slowing down :laughing: :laughing: :laughing: or am I reading into that too much? :laughing:
I’m more concerning about the excessive light we continuously put outside our “caves”. Human evolved with day time/night time cycle. Face it, we’re currently in the progress of day time/not-so-dark night cycle evolution. It’s impossible to get back to the stone age. Let the science and technology slowly find the answer. In the meantime you can try your best to minimize the harmful effect (if there’s any) in sensible and practical ways.
I myself don’t have any problem sleeping/trying to sleep under any light source. The problem is when I wake up, CW hurts my eyes more than warm white.
[Clemence]
Life itself is deadly, everything can kill you, eventually.
I’ll be BBQing tomorrow.
Chris
I don’t have an incandescent to test but I tested a heat lamp with 100CRI and almost no blue light and 0.000 DUV at 2800K. I think incandescent is similar.
SW45K 219B 9080 has very high blue light intensity. I can’t find a 70CRI 4500K to compare with at the moment but it is definitely not a light to shine directly in your eyes.
I haven’t tried the SW35 yet. I haven’t tried Optisolis 6500K. I never go above 5000K unless it is for a pure thrower. I measured sunlight from 3000K to 5700K depending on time of day. Cloudy day can be 6000K+ but I prefer sunlight over cloudy day.
E21A, 2070K, 95.5 CRI, blue peak intensity of 0.07
E21A, 3061K, 96.2 CRI, blue peak intensity of 0.45
E21A 2x2000K and 2x4000K, 2828K, 94.5 CRI, peak intensity of 0.40
The SST-20, 2910K, 96.9CRI has a blue peak intensity of 0.38
The XP-L2 HD V4 7A, 3168K, 72.1 CRI, blue peak intensity of 0.76 and a DUV of –0.0029 (tint is real good btw).
XP-L HD, 2958K, 70.1 CRI, blue peak intensity of 0.39
XP-E HEW Q3 7A2, 3311K, CRI 89.8, blue peak intensity of 0.57
Nichia 219B 3000K 9080, 3391K, CRI 95.2, blue peak intensity of 0.57
Yuji, 3191K, CRI 96.6, blue peak intensity of 0.060
Optisolis 2700K, measures 2973K, CRI 97.5, blue peak intensity of 0.41
Oslon Square 92 CRI 6X tint, 2746K, CRI 91.3, blue peak intensity of 0.29
Oslon Square 96 CRI 6U tint, 2831K, CRI 95.9, blue peak intensity of 0.26
Oslon Square 92 CRI 5Q tint, 3346K, CRI 94.9, blue peak intensity of 0.61
It’s real hard to quantify blue light. The blue peak intensity above is relative to the rest of the spectrum for that emitter. The actual amount depends on the lumen output also. In order to get a good comparison of blue wavelength, you would have to overlay the graphs, which is too difficult and too much work to do. However, I think the blue peak intensity is a pretty good indicator of how much blue wavelengths is emitted by the emitter for these warm white CCTs.