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Impact of color quality from lights

PostPosted: Mon Apr 30, 2018 4:37 am
by Ulysses Paiva
Last time I used one was too long ago. I even didnt have an IR filter at the time, had much lesser knowledge and experience and thought the results were horrible.
Some weeks ago I endend up (for no particular reason) using a 1000w Halogen for a restaurant commercial, shooting delicious dishes, and the colors I got were so... great! The results opened up my mind a bit more and I've been using them a lot since that and always with surprising results, specially for skin tones. I'm amazed how much a cheap light can give me back if you know what you're doing.
I always considered the CRI talk a great deal but now I'm taking it even more serious.
I would like to know what you guys think about it, specially regarding HMI OR these new generation LED with high CRI.

Re: Incandescent/Halogen lights

PostPosted: Mon Apr 30, 2018 5:08 am
by Uli Plank
CRI is not a very reliable indicator for color quality of lights, it's just used by the industry for the lack of a better standard.
Have a look at these very detailed tests (just a recent example, he has dozens of these):

https://www.personal-view.com/talks/dis ... -led-light

Our sun or the type of lights you used are still the gold standard. After all, evolution developed our eyes under daylight, not LEDs ;-)

Re: Incandescent/Halogen lights

PostPosted: Mon Apr 30, 2018 12:33 pm
by Ulysses Paiva
Thanks, Uli.

Yeah, I'm aware of much of the technical aspect behind all of these. I was meaning something more towards whats the practical opinion having used many of these lights and how they performed in real life situations. Like, for example "even though HMI is about 85 to 95 CRI, its 3 times more efficient than incandescent lights so for lighting large areas you would use an HMI and for skin tones you would use an halogen" or "I used an LED from X manufacturer and I clearly could see the nice colors comparing to Y kind of light but I had power issues..."

Thats what came to my mind, kind of what you said, going over the tehcnical aspect and jump to what's really important: how they perform. I think I'm always learning and will die learning and colegues opinions are a great way to share knowledge. If anyone could share their experiences...
What are you using these days, Uli?

Re: Incandescent/Halogen lights

PostPosted: Mon Apr 30, 2018 2:20 pm
by Peter Benson
Ulysses Paiva wrote:What are you using these days, Uli?
Excusing the laughable notion of evolution theory having anything to do with my existence and how I perceive color, I currently enjoy the use of NeoLight LED kit but find the occasion of going back to tungsten yields a no-fuss, aesthetically pleasing result more often than not, and perceptibly, that most especially applies to flesh tones for me.

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Re: Incandescent/Halogen lights

PostPosted: Mon Apr 30, 2018 3:17 pm
by Leon Benzakein
Ulysses Paiva wrote:Last time I used one was too long ago. I even didnt have an IR filter at the time, had much lesser knowledge and experience and thought the results were horrible.
Some weeks ago I endend up (for no particular reason) using a 1000w Halogen for a restaurant commercial, shooting delicious dishes, and the colors I got were so... great! The results opened up my mind a bit more and I've been using them a lot since that and always with surprising results, specially for skin tones. I'm amazed how much a cheap light can give me back if you know what you're doing.
I always considered the CRI talk a great deal but now I'm taking it even more serious.
I would like to know what you guys think about it, specially regarding HMI OR these new generation LED with high CRI.


I am happy to see this discussion.
I have always been romanced by the look of skin tone when using a well balanced HMI or even Kinos with CTB tubes.
I am sure that it has something to do with the frequency of blue light.
Unfortunately not all HMI light is equal. The life of the bubble comes into play.

I find that tungsten balanced lights tend to introduce red and that accentuates the flaws in skin such as rosacea. I can see why you would like the look of tungsten on food products though.
My experience in using LEDs is that one has to be very careful. I have had the good fortune of working with main name brand instruments and even there I have noticed problems with colour temperature consistency.
I have found that some remote phosphor instruments from the same manufacturer have had a green tinge when compared to a similar instrument.
LED instruments are convenient to use but it is definitely still a case of buyer beware and having a lot of minus green gel on hand.

Re: Incandescent/Halogen lights

PostPosted: Mon Apr 30, 2018 4:24 pm
by Ulysses Paiva
Leon, I think that rosacea you mentioned is what I'm flerting with (a good IR filter is taking all unwanted red out, opposed to what I felt when I didnt use an IR filter long time ago). Light with a spectrum pushed towards blue (or even green as the case with some cheappo LED or Fluorescents) gives me a skin closer to a, say monochrome range, or lesser variations throghout the skin tone range. And with tungsten its kind of getting more tonal variations thus giving the impression of richers colors. Might have something to do with the broader redish/orengeish spectrum of that light and the closer to skin tones. Anyways, I'm finding that to be the case even for objects, and that might be related to the CRI and the sorts of.

Yeah, the discussion is always enriching our minds.

Re: Tungsten/Halogen lights

PostPosted: Tue May 01, 2018 6:01 am
by Uli Plank
Dear Peter, you noticed the smiley behind it, did you? I know a lot of Americans are opposing evolution theory.

But fact is that our eyes may react similar to lights with an interrupted spectrum vs lights with a continuous one, called metamerism, see: https://en.wikipedia.org/wiki/Metamerism_(color).

Cameras are different and may react differently, but manufacturers tend to get their color science as close to human perception under continuous spectrum as possible. Consequently, lights with gap spectra may not give the same impression. That said, LED lights have come a long way. Early ones, even from respected sources like LitePad, needed massive magenta filtering without ever getting there. Recent ones, even cheaper brands like Aputure, are much better.

Nevertheless, I share the impression that Tungsten is very nice with human skin when shooting with BM cameras. Why not, if you still have them around and heat or power supply is not an issue?

Re: Tungsten/Halogen lights

PostPosted: Tue May 01, 2018 2:22 pm
by Ulysses Paiva
Yeah, heat and power supply are big concerns (the only concerns for me).
I was lately researching a good LED option to buy but now I'm looking at some mini brutes. :lol:
And I'm so excited they are much cheapper and much better, at least to me. I think I'm gonna keep a distance from LED for some time now.

BTW, I love how fluorescent lights perform in terms of shadow falloff, contrast and etc. Its just that the color is so apart... its a shame. But nothing we cant get with diffusion and boucing with tungsten.

Re: Tungsten/Halogen lights

PostPosted: Wed May 02, 2018 7:51 am
by Mattias Kristiansson
I have a lot of lights: tungsten, real Kino-flo, knock-off Kino flo, HMI and LED. I find it's a lot of guesswork involved. What's the actual color temperature of the tungsten and the HMI bulbs? Is there gaps in the spectrum of the fluorescent tubes and the LED lights? What spectrum does the practicals at the location have?

I'm leaning towards buying a Sekonic C700 Spectromaster to get me away from the guesswork. Even if it is expensive, it seems like a great way to actually _know_ what kind of light I am dealing with.

Re: Tungsten/Halogen lights

PostPosted: Wed May 02, 2018 2:17 pm
by Ulysses Paiva
Here it goes:

Simple_spectroscope.jpg
Simple_spectroscope.jpg (423.66 KiB) Viewed 3295 times


Simple as that.

Re: Tungsten/Halogen lights

PostPosted: Wed May 02, 2018 2:19 pm
by Ulysses Paiva
Hey, Mattias.
We could use a prism to check the quality of our lights. :D
Cheapper than a spectometer.
:lol: :lol: :lol:

Re: Tungsten/Halogen lights

PostPosted: Thu May 03, 2018 12:59 am
by Uli Plank
You may get into contact with Vitaly on www.personal-view.com, he seems to know what he's doing there.
His measurements are quite consistent with the quality we observed from some of the lights he tested.

Re: Tungsten/Halogen lights

PostPosted: Fri May 04, 2018 1:06 am
by Ulysses Paiva
IMG-20180503-WA0010.jpg
IMG-20180503-WA0010.jpg (128.31 KiB) Viewed 3231 times


Enjoying the results.

Re: Tungsten/Halogen lights

PostPosted: Fri May 04, 2018 1:26 am
by Denny Smith
I have always preferred the look of tungsten and Halogen over LED. That said, some of the newer LEDs are looking very good, but my key lights are still Halogen bulb sources.
Cheers

Re: Tungsten/Halogen lights

PostPosted: Fri May 04, 2018 2:15 am
by Ellory Yu
Denny Smith wrote:I have always preferred the look of tungsten and Halogen over LED. That said, some of the newer LEDs are looking very good, but my key lights are still Halogen bulb sources.
Cheers


I share Denny's experience and preference. When I can (indoors) I use tungsten and halogen. I do have a number of LED panels too but not a big fan of them. Don't get me wrong, they have their uses.

Re: Tungsten/Halogen lights

PostPosted: Fri May 04, 2018 2:26 am
by Denny Smith
Yes, like a cool (color green to blueish) shadow fill, where you want to keep the cool blue look, when using 3200K lights.
Cheers

Re: Tungsten/Halogen lights

PostPosted: Fri May 04, 2018 3:04 am
by Ulysses Paiva
Ellory Yu wrote:
Denny Smith wrote: Don't get me wrong, they have their uses.

Those "greenish" lights in the background above the trophies in the pic I posted are LED panels I placed there. :D

Re: Tungsten/Halogen lights

PostPosted: Fri May 04, 2018 9:13 am
by Robert Niessner
I am not a big fan of tungsten lights. But I love my Kinoflos, I have two 4"-4-banks, two 2-banks Divalites and two 4-banks Divalites. And my Rayzr7 300D gives also great colors, blending nice with the Kinoflos.
The same I can say about my Dedolight LEDs. Dedo has done great work on making nice skin tones with their LEDs.

Re: Tungsten/Halogen lights

PostPosted: Fri May 04, 2018 2:05 pm
by John Brawley
I always use Tungsten for beauty work.

When skin tone matters Tungsten always gives the nicest results.

I was recently shooting some errrr tests and for the first time I changed the key to a Sky Panel instead of the usual Tungsten source.

My meter (c700) has been saying the spectral output is very good and it saved me some time because I had to shoot Daylight and Tungsten.

Well.

A certain colour fussy person who always looks at these tests noticed right away that something had changed from my regular setup in Resolve.

Tungsten is very hard to beat. Even though it’s becoming more difficult to even source Tungsten light because it’s so energy in-efficient. (Some territories are trying to ban Tungsten)

https://www.change.org/p/energy4europe- ... gelighting

JB

Re: Tungsten/Halogen lights

PostPosted: Fri May 18, 2018 3:33 pm
by Ulysses Paiva
I've been studying and researching the subject lately, including real physics applied.

I've managed to get some light throught a spectrometer. I used commom lights to compare the results to other known measurements around the web and confirmed the accuracy. Note it doesnt measure the amount of light, so take that into account. For now, I have these 3 results:

This is a home fluorescent light bulb, that has characteristic spikes that may be used for calibration. As seen, it doesnt have a nice spectrum of colors although it has some light throughout the color spectrum.
So, if you put a red ball it will look red, or a green ball it will look green, and so on, but the quality of that color will not be great, it will lack some gradations or gradients between most of them. (kinoflos with CRI above 95 doesnt have that poor spectrum, of course)

Fluo GE.jpg
Fluo GE
Fluo GE.jpg (342.18 KiB) Viewed 2891 times


Here is a home LED bulb, those you usually put on the ceilings fixture. It's not that China-cheap LEDs fixtures, but not an expensive one. You can see it has a much nicer spectrum of colors than the normal fluo, but it lacks some color right where the skin tones fall on the spectrum. Although not as great as the Sun, it certainly can be used and has its place.

LED Philips.jpg
Philips LED
LED Philips.jpg (317.19 KiB) Viewed 2891 times


And thats the direct sunlight, outdoors on a cloudy day. The broader spectrum of all, as already known.
(Notice the sensor has some IR cut filter so data above 650, 700, is certainly shown much lower than real values)

Sol_02.jpg
Sunlight, outdoors, cloudy
Sol_02.jpg (319.38 KiB) Viewed 2891 times


I'm waiting for some new halogen lights to arrive so I can compare to the ones I already have and other kind of light sources. Thats just a start of the study. Lately, I'm using fluos only for hair/back light. Will trust a bit on some (not high end) LEDs and probably build something out of it, maybe for fill and even key in certain cases.

Hope it can help some of you with less knowledge about lights just like me.
Will post more results when I test more.

Impact of color quality from lights

PostPosted: Sat May 19, 2018 4:03 pm
by rick.lang
Ulysses, you mentioned that the image of the overcast day had an IR Cut on the sensor. Which sensor?

For beauty shots I would use the 4x5.6” Schneider 715 IR Cut on the 4.6K sensor to save more deep red in skin tones than the more ubiquitous 680 IR Cut passes.

If the primary concern is knocking down infrared on material, then the old Schneider B+W 486MRC is more traditional and cuts sooner in the spectrum

But with these new ND filters that attenuate infrared as much as visible light, there may be less need to use an IR Cut. Filters like the new SLR Magic ND filters would be a fine example.

As for overhead lights in the home, I just replaced a burnt out halogen light that was 300 watts with an LED using only 8 watts at one-third the cost of the halogen bulb! Not quite as bright but reasonably close. However I dislike the colour spikes in the LED and may go back to the halogen.

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Re: Impact of color quality from lights

PostPosted: Sat May 19, 2018 8:55 pm
by Peter Benson
Uli Plank wrote:Dear Peter, you noticed the smiley behind it, did you? I know a lot of Americans are opposing evolution theory.

But fact is that our eyes may react similar to lights with an interrupted spectrum vs lights with a continuous one, called metamerism, see: https://en.wikipedia.org/wiki/Metamerism_(color).

Cameras are different and may react differently, but manufacturers tend to get their color science as close to human perception under continuous spectrum as possible. Consequently, lights with gap spectra may not give the same impression. That said, LED lights have come a long way. Early ones, even from respected sources like LitePad, needed massive magenta filtering without ever getting there. Recent ones, even cheaper brands like Aputure, are much better.

Nevertheless, I share the impression that Tungsten is very nice with human skin when shooting with BM cameras. Why not, if you still have them around and heat or power supply is not an issue?
Hahaaa! Touché Uli!

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Re: Impact of color quality from lights

PostPosted: Sat May 19, 2018 9:18 pm
by Peter Benson
Uli Plank wrote:Dear Peter, you noticed the smiley behind it, did you? I know a lot of Americans are opposing evolution theory.

Nevertheless, I share the impression that Tungsten is very nice with human skin when shooting with BM cameras. Why not, if you still have them around and heat or power supply is not an issue?


Trust me: Hordes of us Americans are still duped by that irrational ["Life-forms over huge swaths of time is becoming more complex all on its own -- ooh, but the 2nd Law of Thermodynamics is still valid" incoherent monkey-business.

As a near 70 year old descendant of Irish-born Europeans and Peoples sold into slavery from their tribal chiefs in various portions of Western Africa, I find it at once, appalling if not incredulously hilarious that the developers of so-called theory of "evolution" (sic) were vainly bent on making Negroes (sic) out to be sub-human -- apes as it were, despite the obvious differences between animals and people -- posessing far-higher traits that reflect the One Who made us all. Amazing how far man's rebellious nature against Him goes -- erecting self-serving presumptuous notions above the pinnacle of truth and sound reasoning.

~~~

️But on the matter of tungsten lights we've got in the garage (Lowel Tota Lights among them), I'm thinking they have double practical duty when on an indoor shoot during winter here -- providing beautiful illumination and also mitigating against the need to run the furnace in between shot segments!

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Re: Impact of color quality from lights

PostPosted: Mon May 21, 2018 2:17 pm
by Ulysses Paiva
rick.lang wrote:Ulysses, you mentioned that the image of the overcast day had an IR Cut on the sensor. Which sensor?


Rick, the spectrometer was built for lab researching (not specifically for video lights) thus has a good accuracy in its nature. It has a Logitech webcam with a diffusion grating to separate light colors and a software analyses the data. The build instructions suggests removing the IR filter that is built in the camera. But thats only if you need to analyze infrared spectrum, like for beer/food or stars spectrum analysis. In our case, only visible spectrum matters so no need to hassle about built in IR filter. But I thought it was worth mentioning in case someone miss the IR data.

rick.lang wrote:As for overhead lights in the home, I just replaced a burnt out halogen light that was 300 watts with an LED using only 8 watts at one-third the cost of the halogen bulb! Not quite as bright but reasonably close. However I dislike the colour spikes in the LED and may go back to the halogen.

I'm actually researching about new LED bulbs that are high CRI, some from Philips and GE. They seem to be a good option for hair light, fill and sometimes even key with a quality result when you decide to go a low output and soft source as in tight shots or lowlight ones. But I'm still gathering info about them and didnt find any to buy locally, only importing.

Impact of color quality from lights

PostPosted: Mon May 21, 2018 3:46 pm
by rick.lang
Thanks, Ulysses. That Phillips LED bulb spectrum posted earlier looks quite good except perhaps for the deep red. I still suspect that might have something to do with the IR Cut on the sensor.

If I wasn’t so tired after a dinner party last night, I’d get my a** in gear and look at Phillips’ own spectral charts.

John Brawley has mentioned that he wouldn’t use LEDs he’s seen for beauty shots and that’s likely reliable advice but it may only be a matter of time until the full red spectrum is improved. I certainly like the cool running temperature and greater power efficiency but still waiting for a breakthrough LED. Until then...


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Re: Impact of color quality from lights

PostPosted: Mon May 21, 2018 4:03 pm
by Ulysses Paiva
rick.lang wrote:Thanks, Ulysses. That Phillips LED bulb spectrum posted earlier looks quite good except perhaps for the deep red. I still suspect that might have something to do with the IR Cut on the sensor.

If I wasn’t so tired after a dinner party last night, I’d get my a** in gear and look at Phillips’ own spectral charts.

John Brawley has mentioned that he wouldn’t use LEDs he’s seen for beauty shots and that’s likely reliable advice but it may only be a matter of time until the full red spectrum is improved. I certainly like the cool running temperature and greater power efficiency but still waiting for a breakthrough LED. Until then...


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That particular bulb is rated CRI 80 by Philips which was what I thought at first but believed I was guesstimating wrong. I found a test with a similar bulb that had similar findings with the CRI colors scale and the particular deep red almost inexistent while the other patches with a good rating. I think it's good for many situations but not for great skintones and such. And its cheap and easy to build a rig with some of them to give more output. When you have time give a look at the GE HD LEDs, mainly the "Reveal" model. Seems like they give nice colors while weak output. But you can think of many uses for that... (Picturing Stanley Kubrick doing that thing with a single tungsten bulb lighting Jack Nicholson's face in "The Shinning". :lol: )

Re: Impact of color quality from lights

PostPosted: Mon May 21, 2018 10:25 pm
by rick.lang
Thanks for the reminder about the GE Reveal. That could be a good option in some situations!


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Re: Tungsten/Halogen lights

PostPosted: Wed May 23, 2018 11:23 am
by Thomas Koveleskie
John Brawley wrote:I always use Tungsten for beauty work.

When skin tone matters Tungsten always gives the nicest results.

JB



Totally agree . I own a set of large Photoflex Silver Domes with the FV-SL1000 tungsten bulbs and always used them for key light when I could. I traveled all over the place with these 1000W light sets in tow. In particular, these diffused domes are fantastic for skin tones on the fashion and fitness shoots I did. Really better than anything else I tried. The color rendition is so natural. The bulbs are rated at 3200K.