Review of 3 higher CRI 3500K - 4000K LED bulbs

[JoakimFlorence]

Being able to find LED bulbs that have higher CRI in 3500K and 4000K color temperatures can be more difficult. So here is a review of three brands.


Satco (S12417)

This is an LED filament bulb (fully omnidirectional light output).
The specifications for this bulb say 8 Watts, 800 lumens, 90 CRI. I tested both the 3500K and 4000K versions.

The color rendering still feels kind of like average LED light, but a small notch up in improvement. In my opinion the light is "satisfactory" (but I'm very picky about color rendering).
Red colors appear acceptable, more saturated than under normal LED light, but still not really "vibrant".

It has excellent tint, almost like sunlight.

Comparing this to the selectable color temperature bulb, the light almost strangely seems just a tiny notch "yellower" or "warmer", though it's hard to say if this actually has to do with color temperature. And unlike the 3500K and 4000K settings on the color selectable bulb, these bulbs do not have any noticeable flicker.
Comparing this to the selectable color temperature bulb, it seems the Satco may have just a tiny tinge more "warmness" in the light (a feel that's associated with a higher percentage of orange-red wavelengths in the light), but I could be wrong about that, it was just a small impression I seemed to have, it's very difficult to tell for sure. It was not a very big difference. The two are much more similar than different.

It's difficult for me to tell exactly, but I would estimate this light to be exactly 90 CRI (or less than 91 ).


Star Microelectronic Systems

This is a half dome more "directional" LED bulb. The bulb feels extremely lightweight.
800 lumens, 8 Watts"

The color tint of the light from this bulb is not as wonderful as the Satco bulbs. The light somehow does not feel as "soft" or "smooth".
This does not seem as "warm" as the Satco bulb or Ecosmart selectable color temperature bulb (both in the 3500K and 4000K versions). The color rendering seems to come very close, but I suspect the CRI on this might be maybe one or a half point less than the other two bulbs mentioned.
It clearly says "90 CRI" on the packaging box.
While the CRI definitely appears somewhat better than a "normal" LED bulb, the light does not seem as high quality as other high CRI LED bulbs.
I also seem to notice the bulb does not seem to put out quite as much light as the other two bulbs, even though they all are labeled "800 lumens".

The bulb doesn't really have obvious flicker but I perceive there might be some very low level flicker at the very edge of human perception. You would have to be extremely sensitive to even be able to perceive it. It is a little hard to tell and I can't be completely sure. (But it's still far less than the more obvious flicker that develops on the selectable color temperature bulb after it is left on for a few minutes at 3500K or 4000K)


LEDERA Grow Light Bulb

The packaging says "Full Spectrum".

The light seems to be at a little bit higher than 3500K, maybe 3600K.
The appearance of the light has a horrible color tint, like one of those older very low quality 80 CRI LEDs. The light appears just a little "eery orangish" (a little of the feeling of a high pressure sodium vapor street lamp even). Though the light could be described as "white". The color rendering doesn't appear all that wonderful, but despite this I suspect it may contain some longer wavelength coverage.

I don't think the phosphor composition of this was designed with light appearance or CRI in mind.

In terms of orange, red, skin and wood color tone "warmth", I would say this is equivalent to an 89 CRI LED. But in terms of red saturation (how pure red colors can look, rather than orange-red), I would say this is equivalent to a 94 CRI LED.

If the spectral graph on the packaging is to be believed, the "red" phosphor is centered on around 640-650nm. So perhaps while the spectrum does reach more into the longer red wavelengths than other bulbs, there is also less total orange-red light, or at least less red light that the eye can see, since the deeper red wavelengths have less brightness.
(Longer red wavelengths are less orange, which means less can be added before it begins throwing off the overall color tint of the light, making the light no longer white balanced. To be able to counteract this, I think the phosphor formula would have to contain a special (newer generation) SiAlON phosphor that would provide more specific deeper green wavelength coverage, which I do not think this light has. As I said before, I don't think this light was designed for aesthetic appearance and high CRI in mind. What I think this goes to show is that simply just adding deeper red wavelength coverage doesn't always automatically translate into high CRI, it can be a little more complicated than that)

The top of the packaging has 3 empty boxes for indicating color temperature, and there appears to be a manually placed black marker dot marking the box corresponding to "4000K". But the only three options indicated are 3000K, 4000K, and 5000K. So I'm going to guess they just marked "4000K" because, of those three options, that is the one this light is closest to (since there was no "3500K" box option).

The light has no noticeable flicker, so it is very good in that area.

The advertising on the package claims "95+ BALANCED LIGHT SPECTRUMCRI" (with no space between those last words). I suspect what they intended to mean is maybe that it's "equivalent" to 95 CRI, based on the type of red phosphor they used. Not that the light actually is "95 CRI". I think they're just using that to indicate how far into the deeper longer red wavelengths the spectrum of this light has coverage in.

The interesting thing, despite the lackluster color rendering, the light does feel "full", not "hollow", "empty" or "faux white" like other low CRI LED lights. So I think this does show that the human eye can somehow perceive deep red wavelengths (though I'm not sure precisely how) and that it is about more than just "color". This grow lamp is described as "full spectrum" and I would say it has that effect.
In my opinion, I think this "full spectrum" grow bulb could be useful to help alleviate winter depression, more than other normal LED lamps; it's a peculiar psychological effect not altogether the same as color temperature or color rendering.

What else is strange about this light is the light color appears "yellow-orange" even though it is definitely at least 3500K. Whereas a normal 3500K bulb besides it appears rather "neutral white" by comparison, even though you can tell that this grow bulb is a little bluer and higher in color temperature than the normal 3500K bulb. That probably sounds completely paradoxical, but it is what I notice. This bulb somehow has the "feel" and "impression" of a 2700K-3000K bulb, as long as you're not comparing it side by side to other light sources. (But I suppose human perception may have a little trouble accurately judging color temperature after the eyes have adjusted to a light source)
So it seems that having deep red wavelength coverage can cause some bizarre psychological perceptions.

At 1000 lumens and 9 Watts power consumption, that works out to 111.1 lumens per Watt, which would be surprisingly high efficiency. I suspect they may be exaggerating the lumen output. It does not really seem to be that much brighter than a "60 Watt equivalent" ( 800 lumen), so I suspect it might actually be only around 890 lumens in brightness. That would put it closer to 98.9 lumens per Watt, more realistic, I think. (With directional LED bulbs, it might measure the same brightness as another omnidirectional bulb that puts out more lumens, so this might be due to less sophisticated measuring technique by the Chinese manufacturer)

The price of these grow bulbs is very affordable. A 2-pack for $6.

 

[JoakimFlorence]

GreenCreative

The packaging claims 840 lumens, 93 lumens per Watt efficiency, 92 CRI.
It's available in both 3500K and 4000K, but I only looked at the 3500K.

The first thing I noticed about the light quality is there is something about it that makes it seem almost identical to the light from a premium Ecosmart dimmable bulb (or particularly reminiscent might be a better description). (Of course, this light is 3500K and the Ecosmart dimmable bulb is 3000K) I suppose that perhaps should not be too surprising, since the CRI level is about the same. (source for that in this thread )

The level of "warmth" and color rendering from this light seems a tiny notch better than the Star Microelectronic Systems and Satco bulbs. The color tint is between good to great, but not quite as great as amazing as the Satco bulb.

So I would say the CRI level is like just one mark below "great".
If I had to estimate the CRI, I would guess it might be the slightest bit higher than 92, maybe somewhere between 92.2 to 92.6

The weight of the bulb seems a little more substantial (like there may actually be some electronic components in there) but still overall very lightweight.

I can perceive some low level flicker, seems to be just a tiny bit more than the other two bulbs. The pencil flick test confirms that this bulb has flicker.

Now, this is really parsing details and splitting hairs, looking for the most subtle of differences, but if I were to try to compare the light from this GreenCreative bulb to the Ecosmart selectable color temperature bulb, I would say that the light quality from the Ecosmart seems to feel the tiniest bit "softer" and have a very slightly better tint.
It's true the selectable color temperature Ecosmart at 3500K can develop a little flicker, but it's a different type of flicker from the GreenCreative. The GreenCreative is mostly high frequency (maybe 120 Hz), whereas the Ecosmart is a lower more noticeable frequency (assuming 60 Hz) but to me that flicker almost seems to somehow be "softer" and less insidiously annoying. I think I enjoy the Ecosmart light slightly more. However, the GreenCreative might have the tiniest bit higher CRI level, maybe somewhere between 0.2 and 0.4 CRI points higher, if I had to guess, though it's difficult to tell. (And it's possible I could be completely wrong and they have the exact same CRI)


Overview

I hate to say it, but the Ecosmart selectable color temperature bulb compares favorably with these other four brands I have tested. It's definitely not perfect, but I think I prefer the light from the Ecosmart most of all.

(Although if you're specifically looking for a fully omnidirectional filament bulb, the Satco has a great light tint and softness, and I think it would be very difficult to find another brand with filament options in 3500K and 4000K, and with higher CRI, and least in ordinary bulb sizes)

Maybe it's not surprising that the biggest mainstream brand (Ecosmart) would have the best overall light quality, in terms of tint and feel, and having a little less severe flicker than other little-known off brands.
(disclaimer: be aware not all of Ecosmart's bulb models have higher CRI. Their 3500K and 4000K bulb options are only available in ordinary CRI )

 

[JoakimFlorence]

This is a review of an unbranded Chinese-sourced LED bulb. It's sold on ebay by seller "yallindeed" and also on AliExpress (seller "Nanmao"). It must be from a very small niche Chinese manufacturer. The packaging it came in generically says "LED bulb", but there's a sticker over it giving more information. "Shenzhen Weiyi Ligh Co LTD, DIY LED U-Home, High CRI LED". (It lists an address in Shangjing Industrial Park, Guangdong)
The specifications read 4000K, 9W, 850-950 lumens, CRI: Ra 95-98.

I got this bulb because it promised high CRI in 4000K.

The company seems to offer different versions of their bulbs. They apparently have one version that uses violet emitters, and then they also sell an older version that used blue emitter LED to create the high CRI 4000K spectrum. I chose the blue emitter version to evaluate.
The base of the bulb (on the blue emitter version) is made of shiny metallic plastic that is more heat conductive (feels colder to the touch), and has a fin-grill like pattern to help dissipate heat. This was a common design on many of the earlier LED bulbs. I'm sure this company probably does not manufacture their own plastic bulb housings but probably buys them from other companies. It does give the bulb a more "interesting" decorative appearance.

The light is a little more single directional than other half-dome LED bulbs.

I'm normally very good at being able to judge CRI by looking at the light, but for some reason I am having a lot more trouble being able to perceive and estimate the CRI of the light from this bulb. I suspect the fact that it is 4000K has something to do with it. It seems to me that the CRI is at least 93.5 , and it may indeed be 95. I have a very difficult time being able to tell. I can sense that the light contains deeper red wavelengths like a very high CRI bulb (96,97,98 ), but at the same time the red or red-orange colors simply do feel quite as bright and warm as I would perhaps expect they should at this high CRI. In that respect, it seems more similar to the light from a Satco (90 CRI) bulb, or Ecosmart (92.5 CRI) bulb.
I did decide to do a comparison between the Ecosmart color temperature adjustable bulb and this bulb, and apparently this bulb does definitely have a higher CRI than the Ecosmart at 4000K. I noticed an interesting effect on the Ecosmart; the reds look notably more saturated and warmer at the 3500K setting than they do at the 4000K setting. Even though I'd expect they would have approximately the same CRI rating. So it seems color temperature is playing some role in why this 4000K light is not making reds look as rich and colorful as I would have expected them to.
The effect, however, is that this very high CRI 4000K light does not make red colors look as rich as they would under natural daylight. I'd say there is a noticeable shortcoming.

But the appearance of red colors does look very ruby red in color hue (rather than orange-red), so this is an indicator of higher CRI.
(I'm thinking it might have something to do with the phosphor composition, where it is indeed providing deeper red wavelength coverage, but with the trade-off that it is not providing as much visible red light. Because to achieve neutral color balance, the equivalent level of visible red light has to be reduced if that red is a deep ruby-red rather than orange-red)

The company does provide a spectral graph for this bulb in their advertising. (I can't be entirely sure whether this might just be a generic graph of high CRI light the company is using, which would not be an uncommon tactic by a cheap Chinese company trying to look professional than they actually are while saving money, or whether it's an actual measurement from their product)

The tint of the light is nice, it almost reminds me of the excellent tint of the 90 CRI Satco bulbs, but maybe not quite as good. And it's not quite as good as some 96 CRI Oslon emitters I have, but comes close.

The "feel" of the light seems sort of halfway between the yellowish "faux white" feel of ordinary LEDs and the more "full spectrum" territory that very high CRI light is in.

No obvious flicker issues.

Overall the light is nice and nothing to complain about. I can't be truly sure that the CRI is actually 95 or 98, but it does have better CRI than any other blue-emitter 4000K LED bulb I've tested.