[Review] SST-20 in FW3A is divine!

Joshk · 2019-09-19T23:52:03.000Z

Bob_McBob:

but it doesn’t mean it’s what people want for general lighting, especially at night.

I think you are confusing rosy with warm. Warm light is awesome at night. But it’s still neutral.

ToyKeeper · 2019-09-20T02:50:14.000Z

Joshk:

Bob_McBob:

Joshk:

We want our lighting to agree with daylight.

Again, studies pretty clearly demonstrate we don’t want that. It’s extremely useful to have a proper daylight reference in many situations, but it doesn’t mean it’s what people want for general lighting, especially at night. User preference is much more important than achieving the one true neutral tint.

I think you are confusing rosy with warm. Warm light is awesome at night. But it’s still neutral.

If what Bob said doesn’t make sense, you may be confused. But this is not a bad thing. Being confused can be a very useful thing, if one is able to recognize it.

One day, students went into their physics class and the teacher showed them a large thick metal plate with one end very close to a fire and the other end a couple meters away. The teacher instructed the students to feel the metal plate, and they felt that the end near the fire was cooler while the end away from the fire was warmer. So the teacher asked the students to write down a guess about why.

Some students wrote things like “because of how metal conducts heat” or “because of how air moves”, but no one wrote “this doesn’t make sense” or “this seems impossible”. So no one got the right answer… which was that, just before the students came into the room, the teacher had turned the plate around.

The students failed because they did not notice their confusion, and thus ignored the most important clue they had.

Usually, when one is confused, it means that one has a false belief or a false assumption. The sensible way to respond to confusion is by trying to identify what that false belief is… and get rid of it.

In this case, I think the confusion may be caused by the false belief that humans in general want artificial lighting to be identical to daylight (or at least on the blackbody line). The available data on this topic indicates that most people actually do not want this, and instead prefer something a bit more rosy in tint. A perfect blackbody radiator may be ideal in a mathematical sense, but that does not mean it produces an ideal lighting spectrum for human use.

Or perhaps the confusion may be caused by the false assumption that Bob doesn’t know what he’s talking about. But he does, and he’s not confusing duv with CCT.

Joshk · 2019-09-20T02:56:51.000Z

ToyKeeper:

Joshk:

Bob_McBob:

Joshk:

We want our lighting to agree with daylight.

Again, studies pretty clearly demonstrate we don’t want that. It’s extremely useful to have a proper daylight reference in many situations, but it doesn’t mean it’s what people want for general lighting, especially at night. User preference is much more important than achieving the one true neutral tint.

I think you are confusing rosy with warm. Warm light is awesome at night. But it’s still neutral.

If what Bob said doesn’t make sense, you may be confused. But this is not a bad thing. Being confused can be a very useful thing, if one is able to recognize it.

One day, students went into their physics class and the teacher showed them a large thick metal plate with one end very close to a fire and the other end a couple meters away. The teacher instructed the students to feel the metal plate, and they felt that the end near the fire was cooler while the end away from the fire was warmer. So the teacher asked the students to write down a guess about why.

Some students wrote things like “because of how metal conducts heat” or “because of how air moves”, but no one wrote “this doesn’t make sense” or “this seems impossible”. So no one got the right answer… which was that, just before the students came into the room, the teacher had turned the plate around.

The students failed because they did not notice their confusion, and thus ignored the most important clue they had.

Usually, when one is confused, it means that one has a false belief or a false assumption. The sensible way to respond to confusion is by trying to identify what that false belief is… and get rid of it.

In this case, I think the confusion may be caused by the false belief that humans in general want artificial lighting to be identical to daylight (or at least on the blackbody line). The available data on this topic indicates that most people actually do not want this, and instead prefer something a bit more rosy in tint. A perfect blackbody radiator may be ideal in a mathematical sense, but that does not mean it produces an ideal lighting spectrum for human use.

Or perhaps the confusion may be caused by the false assumption that Bob doesn’t know what he’s talking about. But he does, and he’s not confusing duv with CCT.

You are know TK, I’m getting tired of you deleting the relevant parts of my quotes to make me look confused. Let me quote that properly for you to read again.

Joshk:

We want our lighting to agree with daylight. Not have some weird discrepancy.

contactcr · 2019-09-20T03:02:32.000Z

Arguing opinions with opinionated people, why bother. Different people have different preferences regardless of if one is talking about CCT or Duv. Are these studies more than just surveys anyways?

ToyKeeper · 2019-09-20T03:08:08.000Z

Joshk:

You are know TK, I’m getting tired of you deleting the relevant parts of my quotes to make me look confused. Let me quote that properly for you to read again.

Joshk:

We want our lighting to agree with daylight. Not have some weird discrepancy.

My apologies. I may have left out another important bit too, and should quote it in case it was missed earlier.

ToyKeeper:

from research studies, the average preference is about –10 to –15 mduv, and about 5% to 10% of the test subjects disliked a +0.0 mduv light enough to call it unacceptable.

It’s an interesting study, and I recommend reading the entire thing since it’s written in a very accessible manner compared to most research results. The findings are summed up pretty well below though:

Joshk:

Are you seriously complaining about the color of daylight?

Yes. People on average seem to find true daylight less preferable than a slightly rosy alternative.

Joshk · 2019-09-20T03:19:18.000Z

In cases where there is no ambient light from the sun, like a flashlight in a dark house, yea I would believe most people prefer BBL to daylight if that’s what the studies/surveys say. But for the majority of use cases there will be daylight bleeding into the artificial lighting. Like street lights experience. Or houses with windows. Or security lighting. And when you have a BBL based light in one area, and it shifts into a daylight based light (the sun) weirdness happens. Sure, that weirdness goes away when the sun completely sets. But is it worth it? Who cares, because it is just a locus, and you can still have personal preference.

Bob_McBob · 2019-09-20T03:22:32.000Z

Before commenting any further, everyone should read this article carefully. It explains the NIST and other research into colour perception and preference TK and I are discussing and how it has influenced ANSI colour standards. Not only were very negative Duvs strongly preferred at all CCTs by most test subjects, but the cutoff for even perceiving a tint as white is also much lower at 4000K and below. For most people, a perfectly neutral Duv is not preferable after becoming accustomed to the light source. That doesn’t mean there shouldn’t be any neutral lighting, or that a daylight reference isn’t useful, but user preference is ultimately what matters.

https://www.ledsmagazine.com/smart-lighting-iot/white-point-tuning/article/16695905/ansi-continues-advancements-on-ssl-chromaticity-standard-magazine

Joshk · 2019-09-20T03:25:38.000Z

I think we posted at the same time Bob_McBob. Yea I could believe that your vision could shift that far in a completely dark room. But daylight blends in from everywhere in our daily lives.

contactcr · 2019-09-20T03:38:08.000Z

These two experiments on 18 and 21 people appear to just be a way of requesting further funding and research for a more comprehensive study. While I don’t doubt people prefer negative Duv (to what extent who knows) this article is far from gospel and highlights that people like TK are still “not average” and apparently neither are people who prefer something closer to the BBL.

ToyKeeper · 2019-09-20T03:43:37.000Z

I understand that it can be frustrating when things don’t quite line up. Humans evolved on this planet, so human vision should be perfectly aligned with this planet’s natural light source. But it’s not… and that’s okay. Almost nothing ever lines up perfectly. The universe is an incomprehensibly vast gallery of slightly-tilted paintings.

SKV89 · 2019-09-20T03:48:04.000Z

In the past, I’ve asked many non flashlight folks to get their opinion on which beam color they prefer the most. If the CCT is about the same, EVERYONE ALWAYS say they like the below BBL tint more than On the BBL and they dislike the above BBL tint. Sunlight is above the BBL and to me only looks great only when the intensity is high and does not look good when only a faint amount of daylight gets in the house. However, no flashlight can achieve lumen output anywhere close to sunlight so for most cases during night time, I can confidently say the majority will prefer negative duv.

My ideal is slightly rosy with DUV between –0.002 to –0.005. 219B SW45K measures –0.01x on turbo, which is a bit too pink but I still prefer it over a positive BBL. In fact everyone I showed my 219B sw45k flashlights to like the tint better than any on or above bbl 4000K-5000K flashlights.

CLB · 2019-09-20T04:58:42.000Z

Bob_McBob:

very negative Duvs strongly preferred at all CCTs by most test subjects,

Why, exactly, are we invoking merely statistical studies here, especially ones with all of sixteen people as subjects? If these studies are meaningful, it is to lighting marketers, not consumers. As the researchers clearly point out, “Color preference or perceived color is subjective. It depends on the light level, the surrounding environment, or even the observer’s cultural background.” So in what way are preference statistics relevant to what you or I like, or to the relative chromaticity merits of the SST-20 versus the 219B (which is how this discussion started)?

Edited to remove my own confusion between “perceived whiteness” and “preferrred tint.”

Joshk · 2019-09-20T04:30:40.000Z

Ok I stepped away to take some pics.

If we light the right side with “daylight” and the left with rosy, our eyes need to pick a white balance. They pick daylight, and make the left side red-tinted.

Now if our brain sees the rosy side as white, but there is daylight too, the daylight looks green. And again this is weird.

But if we have matching light sources, there is only one white point and all is white.

So unless you can eliminate the daylight from the sky, you are forced to agree with it.
And yes, if you do eliminate the daylight, there is a preference for a rosy lights, but you don’t really notice it’s rosy after you adjust.

CLB · 2019-09-20T04:43:41.000Z

ToyKeeper:

I understand that it can be frustrating when things don’t quite line up. Humans evolved on this planet, so human vision should be perfectly aligned with this planet’s natural light source. But it’s not… and that’s okay. Almost nothing ever lines up perfectly. The universe is a vast gallery of slightly-tilted paintings.

That’s hanging a lot of metaphysical weight on a couple of very small studies. Generally, when things appear not to line up, scientists look for a reason. And they usually find it (or hypothesize it). Are you sure the paintings are tilted?

Bob_McBob · 2019-09-20T05:00:11.000Z

CLB:

That’s not how I read the results:

The figure you posted is from the LRC research on what people perceive as untinted white light at various CCTs. As you can see, this is slightly above BBL at higher CCTs, but quite a bit below BBL at lower CCTs. The NIST research further demonstrates that regardless of CCT and perception of neutral tint, most people still prefer a very negative Duv at all CCTs. Further research has broken this down more, but it is clear neutral light is often not actually preferred at lower CCTs in particular even when carefully controlling for numerous other factors in ways that wouldn’t necessarily be feasible in general lighting, and negative Duv often naturally correlates with these as demonstrated in previous research.

https://www.energy.gov/sites/prod/files/2018/06/f52/RoyerWilkersonWei_SageJournals_August2017_1.pdf

Bob_McBob · 2019-09-20T05:05:48.000Z

Joshk:

So unless you can eliminate the daylight from the sky, you are forced to agree with it.
And yes, if you do eliminate the daylight, there is a preference for a rosy lights, but you don’t really notice it’s rosy after you adjust.

There is a preference for rosy tints at 2700K even after adjustment and careful experimental control of colour rendering in the reseach I posted. You keep talking about daylight, but in the vast majority of cases where I use artificial lighting, it’s either the primary light source or it’s after dark. You can’t just say the sun always comes first in colour preference and only 12 hours of the day actually matter to most people.

Joshk · 2019-09-20T05:09:39.000Z

Yea, I agree with everything you are saying Bob. I never said daylight is first in preference. I was saying that dang thing didn’t come with an off switch.

ToyKeeper · 2019-09-20T08:13:15.000Z

CLB:

in what way are preference statistics relevant to … how this discussion started)?

I think it was mostly because of comments like this, which don’t seem congruent with empirical data:

BlueSwordM:

The SST-20 is better than the 219B in every aspect, even in terms of tint

Joshk:

the 219B is obsolete by all perceivable measures.

Some comments even seem to make fun of those with different preferences:

Joshk:

green-tint phobia

contactcr:

I love these new below BBL LEDs for photography!!!!

I haven’t been particularly nice either. I tend to call out errors and jabs which are probably too minor to really justify attention, and some of my comments probably sound pretty condescending.

… and after starting, the arguments continued when people doubled down instead of updating beliefs to match the data.

To be clear, SST-20 isn’t bad. In some cases, like for some members of this thread, it’s pretty close to optimal. And that’s awesome. But that’s a somewhat atypical result, and the “obsolete” emitter seems to fit the most common case a bit better so it’s inaccurate to call it obsolete.

Of course, none of that matters for personal use. Only individual preference matters there. It’s just a bit misleading to present personal preferences as if they are true for everyone. We could avoid most of this just by weakening the wording a bit, like saying “219B is obsolete for me” instead of asserting it’s obsolete period.

But the disagreements continue because exaggerations continue:

Joshk:

for the majority of use cases there will be daylight bleeding in

Joshk:

[My eyes] pick daylight, and … you are forced to agree with it.

Due to the strength of the assertions made, framing one person’s perceptions as normal and others as aberrant or nonexistent, it sounds as if being in the pink-biased part of the population is somehow bad, like there’s something wrong with people if they don’t prefer 0.000 duv to all other tints. Those people are implied to be invalid or broken. Maybe that’s not the message it was intended to convey, but if not, it would be helpful to word things a bit less aggressively.

Anyway, I hope this episode of “Today’s Argument, Abridged” answers the question adequately.

CLB · 2019-09-20T05:22:23.000Z

Bob_McBob:

The figure you posted is from the LRC research on what people perceive as untinted white light at various CCTs. As you can see, this is slightly above BBL at higher CCTs, but quite a bit below BBL at lower CCTs. The NIST research further demonstrates that regardless of CCT and perception of neutral tint, most people still prefer a very negative Duv at all CCTs. Further research has broken this down more, but it is clear neutral light is often not actually preferred at lower CCTs in particular even when carefully controlling for numerous other factors in ways that wouldn’t necessarily be feasible in general lighting, and negative Duv often naturally correlates with these as demonstrated in previous research.

You’re absolutely right about my confusion between “perceived whiteness” and “preferred tint,” which I realized as soon as I re-read the article, and I have edited my earlier post. Thanks. But I still am not seeing the relevance of these studies to the discussion of the chromaticity merits of two different emitters. If we were discussing the relative literary merits of two books, popularity would be a pretty uninteresting metric. In books, food, and light, I suppose what is popular is not identical to what is “good” from some critical standpoint or another. Now, the question of WHY people would consciously prefer a tint which is perceived as “less white” is interesting.

iamlucky13 · 2019-09-20T05:27:30.000Z

DavidEF:

Joshk:

Ah ha! It’s actually a Locus that merges the BBL and the Daylight Locus. Very cool. It does so by using the 5000k-4000k region to transition.

But… WHY? If the Daylight Locus is more green than the BBL, what is the supposed advantage of “merging” them this way? To say it another way: What light source is anyone measuring that they’d want to skew the “results” in this way?

The most common reference illuminants use different typical hues of daylight for color temperatures of 5000K and above, and the BBL at lower color temperatures.

There is already a disconnect in the typical color temperature ranges of typical light sources - obviously daylight because the sun is the most prominent one, and traditional incandescent bulbs at the BBL. I’d say it makes more sense to bridge that with a gradual transition than a sudden jump.

I’ll stay out of the discussion about duv preferences other than to note reasons to choose one way or the other vary depending on what you are trying to achieve. Since if I remember right, Josh is a photographer, I expect his priority to be producing a good match with the ambient light he has to work with.

I haven’t done much photography, but I was pleasantly surprised to see how well it actually worked for the sake of the photos the first time I made the light from my flash “worse” in terms of typical BLF preferences, but adding a tough plus green filter to better match the fluorescent lights in the building I was taking some event photos in.