I guess I just don’t see a use case for a 3500K bulb with no blue or green color rendering.
If you made a high CRI 3500K bulb, that would be differentiated, but it wouldn’t take much investment for the other high CRI players in the market to adjust their spectrum to 3500K. I can’t really recommend putting in the effort if that’s the case.
Oh I see. To be clear, we intend to only make the Bedtime Bulb products in a low CCT, as that is part of what most people find pleasing at night.
The general purpose bulbs wouldn’t have melanopic reduction most likely. Although we may consider some of the new “flat” SPDs (in the style of Seoul SunLike).
Hey! I tested them last night and I like them very much, the tint is very nice and cozy, they replaced my 2200K edison led bulbs in my bedroom :+1:
There was no visible fluctuation but my house is not that old (1881) so… I can’t speak for the others… 
overall i’m happy with my purchase and I hope they last for years BUT I would love to have a 60w equivalent version or even 80-100 for my living room :sunglasses:
Cool, thanks again! Enjoy, and let me know if you have any more feedback after continued use.
This is interesting guys. It seems ANSI has a C78.376-2014 standard that accepts 3500K as the neutral. I always thought it was odd to call 4000k neutral, as it looks cool to me. It seems this standard lines up with our opinions.
https://www.nema.org/Standards/ComplimentaryDocuments/C78-376-2014-Contents-and-Scope.pdf
It’s interesting for sure, but many (most?) manufacturers still define their spec sheets based on a 3000 K nominal. Despite this, a lot of lighting designers like 3500 or 4000 K.
I think our natural tendency toward round numbers is to blame. I believe if 3500 were a round number, and the next increments were 2500 or 4500 there would never have been any doubt.
since we have read that the bulbs have a flicker problem in USA, and maukka reports they also have a flicker problem in Finland
where in the world are you located?
you did what kind of test?
did you look through a camera, was there any banding?
did you test for flicker, some other way?
Im from canada, I just leave the light on for an hour or two at night before I sleep, no camera just my eyes
Visible brightness fluctuations are rarely an issue in the US. Trust me, we would know about it if it was a widespread issue (we’ve sold tens of thousands of bulbs).
We are testing with ~15 people now across Europe to see if it is repeatable. We are only asking them to observe if there is a visible change.
By the way, the camera banding test is not a very good indication of flicker. My phone camera (Google Pixel 3) will pick up even 2% flicker and make it look like we’re at a disco. Other flagship phones appear to have the same “issue.”
Here are some numbers from the original footage of my video.
First I exported one frame every second:
ffmpeg -i 00000.MTS -vf fps=1,scale=640:480 frames/%05d.png
Then I took the average brightness of each exported frame:
for x in frames/*.png; do convert $x -colorspace gray -format "%[fx:100*mean]\n" info: >> log.csv; done
This is the result:
There are some fluctuations. Not sure if they correlate with the mains voltage, too lazy to OCR the text from the multimeter.
Oh, this doesn’t tell us if there’s a flaw in my setup. But random noise looks different.
edit: I manually compared the brightness and the mains voltage and both correlate with each other more or less. I think this is very similar to the result from maukka.
Thanks for that test. It’s very helpful.
If I’m understanding the graph, the camera is picking up minor brightness fluctuations of around 1% (from a trough of ~52.7% to a peak of ~53.7%). You also notice some slight visual changes in the output just by observing. Is that correct?
I don’t think the absolute values of the scale mean anything (although it is in percent, but percent of what?). The changes are very hard to notice and I think it depends on the situation and the observer if it is noticed at all.
IMHO the point is that the Badtime Bedtime Bulb has a behavior that is not found in other bulbs.
OK, thanks for the clarification. And it may well be a “badtime” bulb in this instance!
Oops. :person_facepalming:
So today i received a bulb from Yeutterg, there were 4 people at home, we all tried to see visible flicker in different scenario (direct vs indirect, dark room vs a little bit of light) all of us failed to see any fluctuation in intensity or flicker, i’ll do some further testing tomorrow.
Is there any kind of typical household load i can put on my electrical system that is susceptible to induce voltage fluctuation ?
I also must say that the light produced is superb for a bedside table or such in my opinion, very soothing and high CRI compared to my 3000k osram led bulbs.
Big AC, fridge, anything with a big honkin’ motor that draws a lot of current on startup (compressor motor kicks in, etc.).
Circular saws and other power-tools are good for that, too.
And vacuum cleaners. They will pull some juice!
For the last days I have used the Bedtime Bulb in my bedroom as the only light and have observed visible output fluctuations several times.