Any LED lighting experts out there? (1 Viewer)

Taghkanic

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I have a technical question about lighting my table, specifically about color impacts of LED bulbs. Hoping maybe there is some tech wizard here who could shed some, uh, light on the problem.

My main table is lit by two suspended fixtures using Philips HUE LED bulbs. The specs on the top of the bulb are 530 lumens, 7 watts, 2100K, 98mA, 50-60Hz, etc.

These bulbs provide a warm, white light with a slightly yellow cast, and are meant to simulate the look of traditional Edison filament bulbs. I use HUE LEDs throughout my home, controlled by the Apple Home app, and am very happy with them overall.

So my issue is this: I’ve been overlabeling a lot of chips with Gear labels, and they look terrific in natural (day) light. But when they are under this 2100K LED light, something about the LEDs seems to desaturate the perceived color on some of the labels—but not on the clay chip bases!

A label which looks like a forest green in daylight goes gray under the LEDs.

I am very happy with my labels. The issue is the lighting. So my options are:

1) Replace the LEDs with traditional bulbs which do not cause the label colors to go gray. (I’d have to experiment; maybe it has nothing to do with the LED type, but the warmth of the bulbs.)
2) Identify a different type of LED which does not create this problem.
3) Play by candlelight? Install neon? Only host daytime games outdoors?

Help! I love my overlabeled chips... Below are some pics showing the stark difference in color perception between daylight and how they look under these LEDs.

DAYLIGHT ON KITCHEN COUNTER UNDER PICTURE WINDOW:

daylight.jpeg


UNDER PHILIPS 2100K 40W equivalent “filament” bulbs:

table1.jpeg


UNDER LED LIGHT, NEXT TO ORIGINAL UNLABELED CHIP:

table2.jpeg
 
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Taghkanic

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Thank you. That’s an interesting thread.

Perceptually, I’m curious why a warmer/lower brightness bulb would have a desaturating effect like that on the label. I would have thought that adding more warmth to the mix would make everything in the room look warmer. And generally it does: For example, in the third photo above, the piece of cloth pictured is a cool battleship gray; but under the 2100K LEDs, it looks almost tan.

But when these lights hit the chips, they affect the base portion of the chips differently from the labels. It may have to do with their texture and coatings, I’m guessing.

Anyway, I’ll get some bluer, brighter bulbs and see what happens. Thanks again.
 

Joe Harris

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I’m curious why a warmer/lower brightness bulb would have a desaturating effect like that on the label.

Well...sunlight is not easily reproduced. 2100 Kelvin is very yellow. Daytime sunlight is quite a bit bluer. A more specific measurement of this is CRI (color rendering index). The closer the CRI for a given bulb is to 100, the nearer the color reproduction will match sunlight. Many LEDs have a CRI of ~80. Such bulbs might work well for basic illumination purposes, but are less useful for accurate color rendering. Try finding a bulb with a CRI over 90.
 

ReallyGoodUsername

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I’m not an LED lighting expert but I can give you useless advice like I’m one. :tup:
 

ATLarchip

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Thank you. That’s an interesting thread.

Perceptually, I’m curious why a warmer/lower brightness bulb would have a desaturating effect like that on the label. I would have thought that adding more warmth to the mix would make everything in the room look warmer. And generally it does: For example, in the third photo above, the piece of cloth pictured is a cool battleship gray; but under the 2100K LEDs, it looks almost tan.

But when these lights hit the chips, they affect the base portion of the chips differently from the labels. It may have to do with their texture and coatings, I’m guessing.

Anyway, I’ll get some bluer, brighter bulbs and see what happens. Thanks again.

Think about how the outside looks on a clear noon day vs sunset. That’s the difference in 5000K vs 2100K lighting.
I would caution about going too cool as it looks more like fluorescent office lighting then.
 

horseshoez

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My guess is that it has less to do with the type of bulb and more to do with the temp of the light emitted. As mentioned above, really the only way to find out is try different temps all way up to about 3700 or 4000 to avoid going too blue and see what sort of effect it has on everything, label color, felt, etc. May not be the color temp you really like but makes the chips and table look better.
 

Joe Harris

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has less to do with the type of bulb and more to do with the temp of the light emitted
This is generally correct, but color temperature isn't as directly correlated as it seems. The wavelengths of the visible color spectrum emitted by a bulb combine to form the Kelvin color value, but the specific wavelengths emitted also affect how each color is visually represented. That is why the CRI value exists - it's the value consumers (generally) actually care about when purchasing bulbs.

Kelvin is the measurement of the light color being emitted.
CRI is the measurement of the color reproduction with the light being emitted.
 

hdgeno

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2100k is probably too low on the spectrum, I would suggest trying 2700 or 3000k. I currently have all 2700k in my house, fairly close to old school incandescent, and I wouldn’t want to go lower.
 

Taghkanic

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Well...sunlight is not easily reproduced. 2100 Kelvin is very yellow. Daytime sunlight is quite a bit bluer. A more specific measurement of this is CRI (color rendering index). The closer the CRI for a given bulb is to 100, the nearer the color reproduction will match sunlight. Many LEDs have a CRI of ~80. Such bulbs might work well for basic illumination purposes, but are less useful for accurate color rendering. Try finding a bulb with a CRI over 90.


I was just at the store, and bought an assortment of bulbs to try. Not one of the many I browsed had a CRI rating on the box!
 

horseshoez

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I was just at the store, and bought an assortment of bulbs to try. Not one of the many I browsed had a CRI rating on the box!

Not a lot of them do but that's when I just go online and go to the manufacturer's website to find it.
 

Taghkanic

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The wavelengths of the visible color spectrum emitted by a bulb combine to form the Kelvin color value, but the specific wavelengths emitted also affect how each color is visually represented.

This is more what I’m trying to get at.

I certainly understand that daylight is generally colder (bluer) than incandescent light. And that some lights are brighter than others, and this may affect not just the lightness/darkness of perceived colors, but to some extent their apparent saturation.

What I don’t understand is the highly desaturated look of the labels vs. the base chips in this warmer LED light.

Basic color theory as I remember it from school is that with, say, pigments, color is additive. If you add blue to red, the red will get more purple (and lighter/darker depending on the values of each, and more/less saturated depending on the intensity of the added color).

If I were mixing paint, adding a warm yellow to a forest green would not result in gray. It would result in a lighter, yellower green.

Light obviously does not operate exactly like pigments... Hence my question. Under these lights, the base green of the Horseshoe chips is perceived about the same or a little yellower, while the forest green of the label is totally losing all of its subtle saturation.

It may be that in lower light, the darker and less saturated colors dull down “quicker” in our perception than hotter, brighter ones.

Anyway, I’ll try three other bulbs out tonight and report back.
 

Colquhoun

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While a warm light may make the room look more yellow, it’s affect on cool colors is desaturation. It’s just complimentary colors at work...in paint mixing, you add orange to dull the brightness of blue. The more you add, the more it grays.
The warmer yellow/orange light is making the cooler green color appear less saturated, and I suspect the green will look much better under a bluer light. However, you may not like the rest of the ambient room light if it’s too blue.
 

Taghkanic

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The warmer yellow/orange light is making the cooler green color appear less saturated, and I suspect the green will look much better under a bluer light. However, you may not like the rest of the ambient room light if it’s too blue.

That makes sense. I was thinking of the forest green as a neutral darker green, but it actually may have more blue and even some red in it than I was thinking, which would logically push it duller when exposed to yellows.
 

Taghkanic

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I tried three types of bulbs from the local big box store. None of these are a real solution, but I thought I’d post the details because they may be instructive.

1) 5000K / 1800 lumens LED.

This bulb cleared up 95% of the color issue. The forest green area of the labels read correctly. But it is totally unsuitable for poker, as I almost lost my sight even glancing at it. I felt like Shelob getting blinded by the Phial of Galadriel.

2) 2700K / 2610 lumens LED.

This made a modest improvement in the desaturating problem. The light was fairly pleasant, though still too bright for my taste. Despite offering more lumens than the one above, it seemed less intense, presumably due to the warmer temperature.

3) 3000K / 1120 lumens incandescent.

No go. Very little improvement over my existing Philips Hue bulbs. The labels looked quite gray.

I’ve been researching CRI bulbs with a 90+ rating and found some possibilities. Just not sure if these will do the trick in a lower lumen and ~3000K combination. I like my game to have some atmosphere, and playing under dentist-office light is not what I’m aiming for... This may take some trial and error.

I’ve seen some mention of “color-pumping” bulbs, meant to deliver truer or higher-intensity color, but am not sure if this is just some marketing euphemism for high-CRI.
 
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Taghkanic

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Still experimenting... Haven’t hit the sweet spot yet, balancing warmth and good color reproduction yet, but getting closer.

I think I may have a solution, though, which is very specific to my light fixtures, which I’ll mention because maybe some others have a similar situation.

My table lights are a classic Danish modern design by Jens-Moller Jensen for Poulsen Lighting. They include a heavy glass canister which screws into the fixture, with a rounded end facing down toward the table.

I’ve used photographic gels in the past to tone down the color of some LED ceiling fixtures in my living room. I’m going to try wrapping the upper half of the glass canister’s interior with a sheet of gel filter, paired with a colder-temperature bulb.

The hope is that this will cast more of a blue, daylight quality light down on the felt, while projecting a warmer, more atmospheric light into the rest of the room. Unfortunately, though I know I have a full roll of such gel filter material somewhere in the house, I can’t for the life of me find it, so I have to wait for an order to arrive. Here’s an illustration of the pendant with the intended effect:

poulsen-jensen-gel.jpg
 

Colquhoun

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This reminds me of when my wife and I were picking a wall color for the kitchen. We both decided a nice grayish blue would look nice. Spent FOREVER picking one that wasn’t too blue or too neutral gray. Got the paint, completed the job and it looked perfect.
Then the sun set, and we turned on the led recessed lights. BOOM, no blue, just plain jail-cell gray.
Oh well, looks great during the day. :rolleyes:
 
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