Color rendering definition, does CCT play a role?

Zappaman · 2018-04-15T05:03:11.000Z

ImagioX1:

I’m not a pro on this subject however I have done a fair amount of research on this exact topic. The short answer to your question is, no a neutral white lamp is not neccesarily going to have a better CRI than a cool white lamp. The ultimate example to prove this would be to look at the specs of an xenon short arc lamp. 6000K and a CRI of >98. While having a higher CCT than a NW led an XSA lamp has a much higher CRI than even the highest high-CRI leds currently available.

The main determining factor for high or low CRI is a lamp’s spectral power distribution, or how much of each wavelength light a lamp has. Lights with massive spikes at certain wavelengths or missing other wavelengths will have a worse CRI than a light that is not missing those wavelengths or has massive spikes.

Wow! BOTH our posts were posted in like the same second imagioX1… :sunglasses:

So in sound reproduction (my area of some expertise as a former recording studio owner), the sought after “glory” of any source is “flat response”— which at face value, means what you record sounds like the source you recorded. Flat response (of a particular instrument/voice/thing recorded) for a multi-track recording is the goal of many engineers. NOT THAT MANY don’t use a bias source (or intentional effects) on a track- MOST do! But the baseline for MOST tracks (instruments) in more classical recordings (for example) is to get a “flat response”.

Your definition of CRI makes a LOT of sense to me, because it seems to be a measurement of BALANCE across the light spectrum- as in the sound spectrum I am describing here. It’s called “flat response” because there is no rise or drop at ANY frequency— thus the recording is tracking the source perfectly— so not up or down, but FLAT (meaning dead on at the exact frequency- in time with the source).

Again… a random correlation here after reading the last few posts.

Balance is in a way, an appreciation for the “whole view” (or whole sound-field in the studio) and it’s not always so easy to identify WHAT is missing exactly; as much as it is to “feel” that (that) “something” IS missing… OR alternatively, too bright (or loud) at a certain frequency.

staticx57 · 2018-04-15T05:29:58.000Z

CRI is just a calculation that determines what colors will look like at a particular CCT by in ideal light source (black body). A green will look different at 3000k vs 7000k but both can be “correct” for example. We are just used to the sun so we perceive ideal as high noon sunlight CCT.

staticx57 · 2018-04-15T05:34:16.000Z

jon_slider:

beam0:

Color rendering definition, does CCT play a role?

no, CCT does not change CRI

whether a light looks Cool or Warm, depends on the White Balance of the operators brain at the time.

IF the operators brain is adapted to sunlight, then a CW light will seem white, and a NW light will seem warmer (yellowish).

otoh, IF the operators brain is adapted to darkness (takes 30 minutes in the dark), then the CW will seem blueish and the NW will not seem yellowish.

the following photos are from iPhone 8 with Automatic white balance. Notice how their color changes based on what they are being compared to. Remember the camera is changing its white balance in every shot. IF the photos were taken with a camera with a Manual white balance setting, then all the colors would stay the same. (and what those colors would be, would change based on which white balance Color Temperature was being used)

A light will look blueish if it is cooler than the white balance of the brain at that time. And a light will look yellowish if it is at a lower CCT than the brain is adapted to at that time.

CRI is a separate subject
Tint is a separate subject also
The following 3 LEDs are all the same 90+CRI, but their R9 (RED) values are not the same. R9 is not part of the 90CRI calculation. The 3 LEDs also have different tints. The worm has the most neutral Tint, the S1 Mini has the greenest tint, and the sw 45 219b has the most, what would you call that Tint?
The CCT of each LED is also different, 4000k for the worm, 5500k for the S1 Mini, and 4500k for the sw45

Tint color is plotted above or below the BBL, the black line (most green top left, most magenta bottom right)
Color Temperature of the light plots along the BBL (most orange on right, most blue on left)
CRI is NOT shown on this chart
White balance is along the BBL, can be at any color temperature, and gives rise to the term Neutral Tint, not to be confused with Neutral White (which is a range of Color Temperatures, Warm, Neutral, Cool)

maukka:

Tint is a perpendicular line to CCT

Zappaman · 2018-04-15T05:36:28.000Z

Again, I stand educated!!!

When I look up to the biggest light source I know of (not the sun, but the galaxy!)… I see black and white. Funny little word eh?

AND… talk about THROW!

jon_slider · 2018-04-15T08:08:45.000Z

staticx57:

Tint is a perpendicular line to CCT

Thank you, could not have said it in so few words!

Reference photo

High CRI LEDs with differing CCT and R9

beam0 wrote: Color rendering definition, does CCT play a role?
jon_slider wrote: no, CCT does not change CRI

I might need to reconsider if what my former self said… should be my final answer…
Is it just White balance that matches better between the Tool and the daylight on a foggy afternoon?

Tally-ho · 2018-04-15T08:36:22.000Z

staticx57:

CRI is just a calculation that determines what colors will look like at a particular CCT by in ideal light source (black body).

No, you should dissociate those two type of measurements of the light. As said before, CRI has nothing to do with CCT.
CRI is based on spectrum of reflectance. A higher CRI means a richer spectrum of reflectance, more “true” colors will bounce back from subjects to a receptor (eye, camera sensor, etc).
We are not talking about the overall tint of a light source or it’s temperature that seems to affect all colors but about its spectrum. Colors are wavelenghts reflected from a light source. The reference is a black body. If another light source lacks wavelenghts, those missing wavelenghts won’t be reflected then some colors will look different because of those missing wavelengths. Hence metamerism.

Tjohn · 2018-04-15T14:36:02.000Z

^ thanks for the new word.

Metamerism (color), in colorimetry, a perceived matching of the colors that, based on differences in spectral power distribution, do not actually match.

Maybe it could be referred to as a natural form of Creative Perceptualization.
_

More chewing gum for the eyeballs:

Since the question in the OP seems to have been laid to rest, and we have decided to go deliciously sideways (this being a “Democratic” flashlight forum, without a Gestapo), maybe we can tie things together in an Exoteric manner?

Zappaman ended his post with:

“Balance is in a way, an appreciation for the “whole view” (or whole sound-field in the studio) and it’s not always so easy to identify WHAT is missing exactly; as much as it is to “feel” that (that) “something” IS missing… OR alternatively, too bright (or loud) at a certain frequency.”

Then:
Jon_Slider ended his post (venturing perhaps where no known BLF poster has gone before) with:

“Do sounds have colors?”

With his permission, I will offer that he previously mentioned his desire to bring white balance into the current type of discussion.
Zappaman has managed to do it succinctly, to the point, and leaving no room for rebuttal.

As to Jon’s query:

Yes, ‘Esoterics’ insist sounds do have colors.
Borrowing from Confucius, and his observations concerning beauty, sounds do have colors, but not everyone can hear them.
I might add, that not everyone can hear the same tune.

In an ‘Absolutists’ forum, this might lead to….
“Prove it to me, go ahead, make me believe it”

^ …seems more like religion, not intended for those with open minds, a burning desire to learn, evolve, and discover whatever it is that brought them to the quest in the beginning.

Could it be that so many treat the CRI, CCT, R9, white balance, and latent image perception tug of war/interaction as an Exact Science, ignoring the inconvenience of personal, subjective sensory perception?

Not even all Esoterics envision the same color progression of the 7 major Chakras, though related to the a shared design of our Human Energy/Endocrine gland system?
How many different methods of measuring, determining, and presenting CRI, RMS wattage and Daylight White exist?

How many valid observations can be offered regarding an individual’s personal perceptions?
Do those with vision impairment hear the same, do the vision AND hearing impaired feel ‘touch’ the same? Are any of their perceptions less, or more valid?

Ironic that most people in the world who need a ’good flashlight, have none, nor any idea of what it means. Just a bulb and battery, maybe even a switch that still works…? Right?

What happens the first time they see one of HWang’s Meteors?

From my repeated experiences, unless you explain things first, they will not notice the difference between my 2A and 3D, care much, or pay attention for that matter.

Do they instinctively know what they prefer, of course!
Do they all see/prefer the same?

The challenge of pushing the flashrocket envelope to shorter burn times, and fuglier flames is merely another WTF? to them.

Maybe Esoteric FlashHeads like us can remember things we forgot after drinking too much Lumen-Aid.

The first avowed Exoteric I met never had a Guru, claimed if he had been born in India, he would have ended up a Yogi. Thankfully he was never limited in that manner.
He ate 2-3 times a week, mostly meat, living on coffee and cigarettes to keep himself ‘grounded’.
Every waking hour to him was described as “being on Las Vegas Strip at night, with no relief”.

He could see better than anybody I have known.
I wonder if he ever needed a flashlight?

jon_slider · 2018-04-15T17:04:48.000Z

Tally-ho:

We are not talking about the overall tint of a light source or it’s temperature that seems to affect all colors but about its spectrum

I agree technically, but have an experiential question

Regarding the 3 hand photos I posted,
I can also see how beam0 could perceive that the warmer LED has better “CRI rendition”

I myself also see that the warmer light appears to have “better CRI rendition”
Is it some factor other than CRI that makes the Tool the better illuminant, closer to foggy afternoon daylight?

can you help illustrate the reason for the difference between the Tool and S1 Mini hand images. Both are “High CRI”.

does the Tool illuminated hand, look more like the foggy afternoon daylight illuminated hand because the Tool 4000k Color Temperature is closer to the daylight photo color temperature (aka white balance?) than the 5500k S1 Mini?

what causes the Tool to illuminate the hand more realistically than the S1 Mini?
is it a difference in CRI, Tint, R9, or just white balance (aka color temperature?)

Is CRI overrated and misunderstood? Is R9 or white balance a more significant variable in making the Tool appear to be better than the S1 Mini at matching late afternoon foggy daylight?

staticx57 · 2018-04-15T17:57:57.000Z

Tally-ho:

staticx57:

CRI is just a calculation that determines what colors will look like at a particular CCT by in ideal light source (black body).

No, you should dissociate those two type of measurements of the light. As said before, CRI has nothing to do with CCT.
CRI is based on spectrum of reflectance. A higher CRI means a richer spectrum of reflectance, more “true” colors will bounce back from subjects to a receptor (eye, camera sensor, etc).
We are not talking about the overall tint of a light source or it’s temperature that seems to affect all colors but about its spectrum. Colors are wavelenghts reflected from a light source. The reference is a black body. If another light source lacks wavelenghts, those missing wavelenghts won’t be reflected then some colors will look different because of those missing wavelengths. Hence metamerism.

CRI is a match of the colors between the light source being measured and an ideal light source (black body) at the same temperature. It is why both the sun and an incandescent light source has a CRI near 100, even though colors are perceived vastly different.

DavidEF · 2018-04-15T18:46:05.000Z

staticx57:

Tally-ho:

staticx57:

CRI is just a calculation that determines what colors will look like at a particular CCT by in ideal light source (black body).

No, you should dissociate those two type of measurements of the light. As said before, CRI has nothing to do with CCT.
CRI is based on spectrum of reflectance. A higher CRI means a richer spectrum of reflectance, more “true” colors will bounce back from subjects to a receptor (eye, camera sensor, etc).
We are not talking about the overall tint of a light source or it’s temperature that seems to affect all colors but about its spectrum. Colors are wavelengths reflected from a light source. The reference is a black body. If another light source lacks wavelengths, those missing wavelengths won’t be reflected then some colors will look different because of those missing wavelengths. Hence metamerism.

CRI is a match of the colors between the light source being measured and an ideal light source (black body) at the same temperature. It is why both the sun and an incandescent light source has a CRI near 100, even though colors are perceived vastly different.

So… CRI is related to CCT, but is not affected by CCT. You might say the CCT of a light source is the zero point for measuring the CRI of that source (because CCT is ‘defined’ in a specific way).

Tjohn · 2018-04-17T07:55:33.000Z

Zappaman:

…….seeing a deer’s antlers through the trees. IF you could see them as a true solid color (without any shadowing or variation in texture) they would be a LOT easier to find looking through the best binoculars. But they are well designed and they are very hard to see— until you see them— THEN your brain “maps” that wavelength and specific texture.

So, a higher CW light is going to see the most CONTRAST over-all (I think that is the correct description)………

My Cool White ZL CREEns are also the best for hunting and destroying blood sucking mosquitoes…

Boaz · 2018-04-19T03:02:41.000Z

Look at my hand ....look very closely ... The hand is making you very sleepy .

just concentrate on the hand ...look at all the pretty colors.you're going deeper and deeper into the cri zone ...GET OUT !!!

The Flashlight ..,,where's your stinkin flashlight ?

Zappaman · 2018-04-18T01:03:11.000Z

I like his hand :sunglasses: It bares pretty jewels… never gets old.

Tjohn · 2018-04-18T19:58:12.000Z

Boaz,
I’ve heard his manicurist has other talents, needs help advertising, and ate all of Jon’s Skittles.
(He hid the M&Ms when his housecat went on a diet.)

Maybe if we photographed our own hands, he wouldn’t need to post his anymore.
(Go easy on yourself if the cartoon was meant to be self deprecating)

Are you French?
I’m from Ohio, along with Wilbur and Orville.
Here in Brazil everybody grows up learning Santos Dumont was the first man to learn to fly, but had to go overseas so the French could take credit.

jon_slider · 2018-04-18T21:30:58.000Z

Zappaman:

pretty jewels

thanks for your kind words

Re: Color rendering definition, does CCT play a role?

testing some different auto white balance effects, around 2pm on a sunny day in Paradise, indoors, outdoors in direct sun, and a couple outdoors in the shade

I would say yes, changes in white balance produces changes in perceived color
bottom right is direct sun, I prefer the bottom left, but the indoor top right is closer to the full sun

the jewels are Baltic Amber, Mexican Turquoise, and Tibetan (Italian) Coral

Barkuti · 2018-04-19T01:22:21.000Z

Boaz:

…

…

With regards to the missing part above (LoL!):

Kruithof Curve @ Wikipedia

Cheers

Tjohn · 2018-04-19T08:19:00.000Z

Barkuti:

Boaz:

…

…

With regards to the missing part above (LoL!):

Kruithof Curve @ Wikipedia

Cheers

Lol…
Lots of missing parts in that post since offering the self effacing illustration yesterday.
M&Ms, Skittles, personal offenses included….

Along with the rude button, a warning about thread incongruety would come in handy.

Correllux · 2021-12-27T00:25:07.000Z

Wow, old thread.

Maybe of interest, I just stumbled on this video the other day while watching one of his others. He’s taken three high-binned XHP50 emitters in 5000K with the three available CRI options (70, 80, 90 with Cree) and tested them with a (legit…$$:money_mouth_face: spectrometer. Not a completely perfect test but he covered all the bases he could. His goal was more about whether the CRI would affect recording/viewing on video, not so much about viewing with the eye as we do with flashlights, but it’s still a neat test and I don’t recall seeing something similar. The spectrographs are probably the most helpful.

I’ll counter Rayfish again as far as the value of higher CRI….it’s helpful and sometimes very important in many more things than skin tones. There has been a big shift in working trades toward higher quality light as soon as they started to become available in the lights/models/styles they tend to favor. Nobody has to like or want higher CRI, that’s fine, but don’t discount its value or importance…imho.

Lotus_Darkrose · 2021-12-27T00:45:43.000Z

rayfish:

to convince you cri is the most important thing in the world of flashlights. Its like saying that plane exhausts are chemtrails and they determine the weather.

Really? C’mon man…The horse is already dead.

Unheard · 2021-12-27T08:41:45.000Z

It seems rayfish is on a mission.