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New LEDs near the elevator, at Azrieli Haifa mall

New LEDs near the elevator, at Azrieli Haifa mall

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These LEDs causes me a lot of eye strain, and I got angry and thought about ways to smash them into pieces:

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Album name:dor123 / LED lighting (Except road lanterns), LEDs in general, lasers, flashlights and other lighting gadgets
Keywords:Lanterns
File Size:475 KB
Date added:Nov 17, 2017
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Date Time:2017:11:16 18:20:10
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merc
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Nov 17, 2017 at 12:02 PM Author: merc
We've had these (or very similar ones) installed last week in a basement corridor and in front of lifts in the building where I work.
Yeah, they're unnecessarily (absurdly) bright. You almost need sunglasses to pass that place.

I can imagine the thinking of those who have chosen them. Say there had been worn 2x 20W CFL in dirty and yellowed downlighters before.
"Hey - the light here... let's make it better. We need to double the wattage!"
"Look at those 80W LED downlighters - let's put them here!"

But they forgot the CFL were worn out, the fixtures were all dirty and yellowed and the LED efficacy is 2 times higher than CFL and throws all the light down without reflection losses. That way they haven't doubled the illumination level but could possibly made it like 10 times higher - far beyond the needs of everyone and causing the eye strain.

Not a misoLEDist...

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Nov 17, 2017 at 12:40 PM Author: Ash
Wait isnt this in the underground parking of Cinemall ? (i think the entrances from the underground to the mall had windows just like in the photo ?)

They used to have 1x36W Fluorescents there, now 2x18W LED tubes (each 18W tube being "36W Fluorescent equivalent" according to its labeling, which is grossly misleading), atleast in the area i seen... Not sure what they save there except a few Watts of ballast losses, but the lighting is much worse now



Your imagination is nearly exactly what happens, with few corrections :

- LED diffuse White panels are much glarier than CFL cans with good reflector optics. They make glare which the CFL cans never made (neither when new, or when old and dirty). The glare impacts vision and it cannot be treated neither by rising or lowering the wattage, since it scales together with the overall lighting level, and since the eye pupil adapts to the overall lighting level, the effect of the glare on the eye remains absolutely constant

- LED spectrum strains the eye and impacts vision, and therefore is less preferrable than CFL spectrum. I won't bring the whole discussion here

- Some LED panels (the cheaper ones, which are very often the ones installed...) are incredibly inefficient in LED terms. Some dont give any efficiency advantage over the PL's (when the PL's are in good condition)

- The fact that PL lights could degrade to giving as little as 1/5th of their original output before this started bothering anyone, means that atleast 1/2 the energy could have been saved in the 1st place by using 1xlamp downlighters instead of 2xlamp ones (and since 2xlamp downlighters have quite significant losses of light behind the lamps, the change to 1xlamp wouldn't even drop the light levels in half). Most LED conversions promise around 1/2 energy savings as well...
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Nov 17, 2017 at 01:22 PM Author: merc

- LED diffuse White panels are much glarier than CFL cans with good reflector optics. They make glare which the CFL cans never made (neither when new, or when old and dirty). The glare impacts vision and it cannot be treated neither by rising or lowering the wattage, since it scales together with the overall lighting level, and since the eye pupil adapts to the overall lighting level, the effect of the glare on the eye remains absolutely constant

- LED spectrum strains the eye and impacts vision, and therefore is less preferrable than CFL spectrum. I won't bring the whole discussion here


I don't think the LED panels at my place are particularly glary - the diffusers work well. But even if I look down (even if I had a baseball cap on my head), the floor and the walls are still insanely overlit. It's almost as if you stepped out from a dark room to a summer midday outdoors. I think all the light sources strong enough would cause about the same eye strain.

As for the LED spectrum (for the others) - it's improved a lot since the humble attempts to make white light like 7 years ago and before. My parents still have such an old corn LED in their bathroom (meaning toilet) and it's indeed a light that could make you to throw up.
Most people here now have LEDs at home, in their offices, in their laptop screens or smartphones and quite happy with them (if they last long enough...).

Some people could possibly be oversensitive to LED spectrum. It could be (rarely) because their eyes are different and mostly it's in their head (read a juicy article about bedbugs and you'll start to scratch)...

Not a misoLEDist...

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Nov 17, 2017 at 02:11 PM Author: Ash
Diffuse LED panels are glary because they are a bright White panel you see from every direction, the background being un illuminated ceiling. In contrast, PL downlighters have good reflectros, the best of them are so effective that when viewing from the side you can't tell if the luminaire is working or not

When you look across the illuminated space, the results are greatly different :

The usefull visual information is in the area, not including the luminaires themselfes

- With glaring luminaires in view, the glaring luminaire is in contrast to all the rest of the area. So all the usefull information is squeezed in the brightness range which is everything but the luminaire. (If we would talk of this like computers, we would say that the luminaire is 255 and all usefull information is squeezed in the 1..5 range)

- With invisible (dark) luminaires in view (so not really in view), the entire contrast range represents the information in the room

The over illumination makes eye strain worse but the root source of the problem (one of them) is still the optics which allow the glare, since only varying the lamp power scales the glare and the usefull light in the same proportions...



The LED spectrum is less desirable than that of most discharge lamps becaue of how it is distributed. Most people dont care, some (mostly old people ?) even do like it - I am not entirely sure why, but i do have 2 explanations :

- They like the eye strain feeling, since they feel it as a sign of the place being "well lit" instead of as a strain

- They have cataract which reduces the quantity of Blue entering the eye. Under LED lighting, there is much more excessive Blue, that it balances the effect of the cataract, so they see everything Whiter

But it does not change the fact that they are accepting worse spectrum from the new product. For some applications the spectrum of all LEDs is good enough, including the 10+ years old ones. For other applications, the spectrum of LEDs is "good enough" in view of many users but it really isn't as good as other light sources provide



I think in displays the light quality is not as much a problem, why - lets compare this to sound :

There are various technologies used to store and play back audio. Some peeps demand things that may improve audio quality like having the record in as high resolution as possible and using specialised (e.g. tube) amplifiers to reproduce it. Some take it to absolutely senseless ridiculous witchcraft extents

Personally i think, that for average music playback, even something far from perfect (cheap headphones, amplifier integrated in the codec IC) is good enough to enjoy music. Perhaps even i can tell that the sound is not the greatest (though i dont really care), but i find it perfectly acceptable since it is just a recording and what i have is good enough for enjoying it. Same for phone calls - The sound quality in the phone is not great at all, but it is perfectly sufficient for the application

What i wouldn't find acceptable at all is, if i watch a live playing band (real people in front of me) playing instruments, and without any electronics at all between us, somehow the sound is as crappy as with the cheap headphones. Or when talking to somebody in person, and his talk becoming unclear as if there would be a phone call with bad reception between us. I.e. if somehow magically the real world becomes crappy

The difference between general application lighting and LCD backlights is, that general application lighting lights up the real world. There isn't an audio equivalent to this, because there is no "luminaire"-equivalent needed at all to percept any sounds in the real world. In general application lighting, having good CRI with poor spectrum is very bad (it can be compared to, for example, having blurred vision, but blurred in the color recognition dimension instead of in the X-Y dimension). In displays, displays are nothing but an instrument to represent some recording (photos taken with a camera, drawn graphics, ...), nothing more. So there pretty much everything that can represent whatever poor resolution of R, G, B that the panel can produce is good enough
merc
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Nov 17, 2017 at 03:23 PM Author: merc

- With glaring luminaires in view, the glaring luminaire is in contrast to all the rest of the area. So all the usefull information is squeezed in the brightness range which is everything but the luminaire. (If we would talk of this like computers, we would say that the luminaire is 255 and all usefull information is squeezed in the 1..5 range)

That's right but I said the luminaires weren't in my view. The problem isn't that I can't see well because I'm blinded by some glary lights. Problem is there's too much light at once and the eyes have to adapt to it immediately.


The LED spectrum is less desirable than that of most discharge lamps becaue of how it is distributed.

The LED spectrum is definitely less desirable than natural daylight. Incandescent light is probably also better (if you can tolerate the subdued blues). The rest is a question. Some people complain about fluorescent lighting in offices, some other would probably complain about LEDs. Low CRI HID lighting has indeed lots of critics...


In general application lighting, having good CRI with poor spectrum is very bad

Sorry that's difficult to imagine. Sounds like an oxymoron. That's like if colours didn't respond to the light spectrum.

Not a misoLEDist...

dor123
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Nov 17, 2017 at 11:16 PM Author: dor123
These LEDs are located at the parking lot and near the elevator of Azrieli Haifa mall, Ash. This isn't at the Cinemall mall.

I"m don't speak English well, and rely on online translating to write in this site.
Please forgive me if my choice of my words looks like offensive, while that isn't my intention.

I only working with the European date format (dd.mm.yyyy).

I lives in Israel, which is a 230-240V, 50hz country.

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Nov 18, 2017 at 04:54 AM Author: Ash
Problem is there's too much light at once and the eyes have to adapt to it immediately.

This isn't a problem with light level changes on the order of 5x..10x, only far more significant changes

The LED spectrum is definitely less desirable than natural daylight. Incandescent light is probably also better (if you can tolerate the subdued blues). The rest is a question. Some people complain about fluorescent lighting in offices, some other would probably complain about LEDs. Low CRI HID lighting has indeed lots of critics...

Incandescent is, in fact, an example for your next question :
Sorry that's difficult to imagine. Sounds like an oxymoron. That's like if colours didn't respond to the light spectrum.

The CRI of Incandescent is 100, but it is very lacking in the Blue

In contrast, the CRI of SON is around 20..25 and the light is Yellow color, yet it represents Blue even better sometimes. The way i think this happens is a correction process happening in our mind. This correction responds to the preceived CRI, not to spectrum :

- Under Incandescent light, the CRI is high (different colors in the surroundings are visible) so we believe that what we see represents what there is. When a Blue object is under the light it will appear dull, but we believe that it indeed is dull

- Under SON light, the CRI is low (everything appears in shades of the SON light) so we pick the subtle still visible differences, and extrapolate from them to what the color would have been. Since this happens in the subconscious, it just results in us seeing colors well under SON (well above what we would expect thinking of it as Yellow light and not knowing about the correction process)



Generally, there is a mismatch between CRI, ability to see colors properly (with the correction in action) and actual light quality :



CRI is an artificial unit, made by calculations based on few values in the D-chart. It's been designed to be representative of a would-be empirical test : A test sheet with 100 color samples is presented under the light. The number of different shades that can be identified is the CRI (same shade in different brightness still counts as same shade). So for example, if CRI would go between 0 and 4, the test sheet contain 4 color samples, and under the tested lamp 2 look the same shade and another 2 look the same shade, then the CRI would be 2. I see 2 places where an error is intoduced into the method :

1.
The color samples are printed with pigments, which are strong colors and have narrow reflection spectrum, but most objects around us have wide reflection spectrum where only the overall balance shifts more or less towards some color. For example, Blue sky is nowhere near strong electrifying Blue, it is just Blue-r than neutral

Lamps with continuous emission spectrum (Incandescent, LED), even if it is not uniform from 400 to 850nm, would always cover the reflection spectrum of the test sample, allowing it to show its color (maybe darker than it really is, if it is off the peak emission of the light source, but still the correct shade)

Lamps with discontinuous emission spectrum (Most discharges) would miss any test sample which reflection spectrum falls inbetween the peaks of the light source reflection spectrum

However, for evaluating the overall balance of an object that reflects to some extent the entire visible light range, a light source which covers uniformly as much of it as possible (even if discontinuously, i.e. an array of sample points spread uniformly through the visible light range) would be preferrable over a light source with continuous but extremely non uniform spectrum

2. Since the 100 samples test is only a theoretical test and not performed in real life, its not clear how well the calculated values would even reflect its results, and how consistent would the error be (under different light sources which have different oddities, the test might have error sometimes in one direction and sometimes in the other)



Light quality is a qualitative measure (there is no scientific way to evaluate it), and depends not only on the light, the objects under the light, but also on its application. What's more, it is affected by the choices of lighting outside of the area where we are measuring the light quality :

If a shop and its parking lot are illuminated by the same White light, they look the same and both the good and bad aspects of the ligth look the same

If a shop is lit with MH and its parking lot with HPS, then when walking from the parking into the shop, crossing the door into the shop changes the light and it appears as higher quality light with lots of color information, so good for the application in the shop. When walking from the shop back to the parking lot, the light changes from White which shows many details in everything, to Yellow which lowers the level of distraction from the surroundings, lowering the quantity of information which is irrelevant to finding the car and driving it

If the shop would be lit by HPS inside (as well as the parking lot), it would be something like : When walking into the shop, we would very actively be using the correction process to choose our stuff in the shop under the Yellow light. The light is inadequate for the application, but lets say we succeeded in doing our business in the shop anyway. When walking back from the shop to the parking, there is no change in the ligthing, so the same looking into every detail and highly active correction process would possibly distract from finding and driving the car instead of helping it
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Nov 18, 2017 at 03:38 PM Author: merc
Lots of imaginations and theories, sorry.

Metamerism is indeed a factor that could possibly play against light sources with line spectrum. But still...
The only correction our brain is capable of is an "object to colour dictionary" it has recorded through experience. It's unidirectional - it can translate a tomato to red, a carrot to orange and your brown shoes (since you know they're brown) to brown. It doesn't work in reverse - a small sample (if not characteristic by it's texture but only by its colour) can't be translated to an object. A small visible pieces of a brown polished leather and a tomato may not be discernible under some light (say a SON lamp).
If you are able to pair socks (from a heap after washing and drying) with similar colour shades under SON light so that they will really match under sunlight, your brain must be supernatural.
And you must be joking with the lower CRI light helping you to find your car...

I like your sound analogy. Imagine a crappy component (PA, headphones, ...) that would make +20dB bumps - say at 200Hz, 700Hz and 3000Hz and suppress by -20dB the rest. You listen to your favourite music so you know - here should be this, there should be this and this should sound in a very different way.
You can "compensate" by your knowledge but... would you really enjoy such a distorted sound? Install Audacity and try that. The same situation is with low CRI lighting. Incandescent lighting could be like small speakers suppressing bass sounds. Not great but still more acceptable than so much distorted sound.

A couple of years ago I spoke with a guy who had been working night shifts in a SON floodlights only lit factory hall. While he only assembled colourless metallic boxes (operations like cutting, punch bending and spot welding), he told me that staying in such a hall for 8 hours was pretty nauseating. It was a great relief for him when they moved to another hall, lit by MH highbays.

It's pointless to replace perfectly working HPS street lanterns in a good shape with LEDs. Just to replace them.
But if you don't need to mix light colours & have LED lanterns proven as reliable & have LED lanterns for reasonable price - then it's also pointless to do new installations with worse quality lighting.

Not a misoLEDist...

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