itchaboyagain
Member
- Joined
- Oct 15, 2020
- Messages
- 48
Finally! This has been several months in the making, and I'm so excited to share it with all of you.
As you’re probably aware, most light sources don’t come very close to mimicking the Sun’s full spectrum of light:
The typical LED spectrum has a large blue spike with a dip in the turquoise region, also very little red.
Light, especially bright full spectrum light, is necessary for all kinds of things, not least of which is our circadian dependent processes like sleep, hormone secretions, and mood.
Since many of us spend most of our time inside in our home or work offices, I wanted to know how close we could get to mimicking natural light indoors?
I ended up testing around 70 or so lights in this endeavor. And since I’ve run out of lights to test, I can now happily share with you the data from those tests as well as my thoughts, findings, and advice on how to go about using this information.
Google Sheets: Light Bulb Test Data
Inside you’ll find some parameters you might not be familiar with, so here’s what I tested for:
How to Replicate Full Spectrum Sunlight Indoors
Here are some of my thoughts on the lights I tested:
Alright, I'll end this with my current office setup.
And here are the spectral graphs from this setup:
Here's the info from the UV light output for those interested:
1 ft: 3.5 UVI
2 ft: 1.5 UVI
3 ft: 0.8 UVI
4 ft: 0.5 UVI
5 ft: 0.2 UVI
Well, I think that's about it!
One more shameless plug to the guide I wrote up about all of this:
How to Replicate Full Spectrum Sunlight Indoors
Hopefully you found this information useful! Have a great week!
As you’re probably aware, most light sources don’t come very close to mimicking the Sun’s full spectrum of light:
The typical LED spectrum has a large blue spike with a dip in the turquoise region, also very little red.
Light, especially bright full spectrum light, is necessary for all kinds of things, not least of which is our circadian dependent processes like sleep, hormone secretions, and mood.
Since many of us spend most of our time inside in our home or work offices, I wanted to know how close we could get to mimicking natural light indoors?
I ended up testing around 70 or so lights in this endeavor. And since I’ve run out of lights to test, I can now happily share with you the data from those tests as well as my thoughts, findings, and advice on how to go about using this information.
Here's the data for your viewing pleasure:I should say the color spectrum data could have been better collected. For example, I didn't use a reflector dome and I didn't wait for the light to heat up before taking readings. But the point was simply to verify the rough spectrum read-outs, so I'm not that concerned with things like accurate duv.
Google Sheets: Light Bulb Test Data
Inside you’ll find some parameters you might not be familiar with, so here’s what I tested for:
- CRI: This is the Color Rendering Index and compares how well an artificial light source reflects light from 15 color samples when compared with a natural light source. ”Ra” is the total score and the highest this goes is 100, which would be identical to sunlight.
- TM-30: This is basically a newer version of the CRI standard and uses 99 color samples (this time from actual real world objects) to calculate a “Fidelity” score with a max of 100, similar to CRI. However, it also gives a “Gamut” score with 100 being identical to the saturation of sunlight, the gamut score can go over or under 100 for this reason.
- Flicker Percentage: This is the most popular way of measuring flicker from a light source. I’ve included scores with dimmers without dimmer and while dimmed. There we're a few bulbs I missed this on as I returned the device I was using for testing purposes.
- Flicker Videos: I've taken slow motion videos of all the lights I tested
- RF Interference: Very few lights produce RF interference, however since I’m normally quite mindful of man-made EMF I wanted to find a light source that isn’t producing tons of RF for no reason other than sloppy engineering.
How to Replicate Full Spectrum Sunlight Indoors
Here are some of my thoughts on the lights I tested:
- The Shanpu Z0850/55Pro and the GE Sun Filled bulbs are the best on the market right now. Here’s a comparison of these lights compared with the spectrum of natural sunlight:
- As you can see, the Shanpu Z085o/55Pro is a spectacularly realistic LED. However, it's kind of a pain to buy as 3rd party TaoBao agents aren't super user-friendly. They're also fairly expensive and the lumens per watt is lower than most other LEDs, so you need more of them to achieve a better lux level, which of course jsut raises the cost more.
- All in, you're looking at like $600 to put out 10,000 lux from these. However, this is very high quality light, with no noticeable flicker. If you like paying for the good things in life, this is it!
- The cheaper and more accessible alternative is the GE Sun Filled lights. At $8-10 a pop, higher luminous output and available on Amazon, they're a great option for someone looking to fill their home with more realistic light. A potential downside is that they do have invisible flicker a bit in the 120Hz range, which could potentially cause sensitive people issues. I personally use these lights and haven't noticed any negative effects, but that doesn't mean they aren't there.
- NorbSmile also uses the SunLike diodes in their bulbs, but their offerings cost more than GE and flicker more as well, so I don't really see any reason to purchase their lights. I did email them about the clicker, and they said they'd be looking into it.
- I was initially very excited about the Sylvania Natural bulbs given the claims and price point, however, I encountered several issues. They’re outright lying about the SPD these give off. The 8w, 11w, and 13w 5000K A19 bulb all have a generic blue pump phosphor blend SPD, as you can see below. I’ve emailed Sylvania asking for an explanation, and have yet to hear a response.
- I also measured 16 of the 8w 5000K bulbs, and found each one had a flicker rate of 12%. None of the other Sylvania bulbs had flicker, as advertised, so this was unexpected. This shows a pretty severe lack of quality control in my opinion, seeing as how one of the big advertising features of these lights is the low flicker rate and dimming capabilities.
- I tested several of the leading contenders for the low-blue light bulb market. I think dim, low-blue lights in the evening are important. However, I’m not a fan of red and orange lighting, I find them very unnatural and uncomfortable personally.
- All the warm low wattage LEDs I tested had an insane amount of flicker, so these were a no-go.
- The Bedtime Bulb is an interesting product, however I think they’re too bright for nighttime use, even the lower wattage version, and the custom phosphor spectrum they accomplish isn’t really that special.
- In the end, the low wattage incandescent bulbs are the best evening light option in my opinion. The 7w bulbs for example don't exceed 10 lux even at a distance of 2 feet, which is perfect for evening use.
Alright, I'll end this with my current office setup.
- I've built two large DIY chandeliers with six GE Sun Filled bulbs and one 53w halogen each. Though I think I'd like to make another... This gives the room most of its lux.
- I also have a floor lamp with three halogen BR30s pointing towards me for more full spectrum infrared exposure, it gives off a pleasant warmth at around two feet.
- And finally, I have a 48" UV reptile light mounted to the corner of my ceiling molding, spraying the room with a trace amount of UV light.
And here are the spectral graphs from this setup:
Here's the info from the UV light output for those interested:
1 ft: 3.5 UVI
2 ft: 1.5 UVI
3 ft: 0.8 UVI
4 ft: 0.5 UVI
5 ft: 0.2 UVI
Well, I think that's about it!
One more shameless plug to the guide I wrote up about all of this:
How to Replicate Full Spectrum Sunlight Indoors
Hopefully you found this information useful! Have a great week!
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