Color Meter Weirdness

[Richard Andrewski]

It has to do mainly with time and resources available and how they should be most wisely spent. Our customers appreciate our fluorescent fixtures and tubes and have not been telling me they need to be different; and that has been a popular product. At the moment though, I think my time is most wisely spent on LED projects because that has been even more popular.

As far as the other bulbs mentioned, I would hope that Osram or Philips could come up with something different or innovative. How large of companies are they? How many employees do they allocate to R&D? What is their revenue every year? Bulbs are their main specialization or a very big part of the company in any case. My main specialization is fixtures for film and television and yes we do have some bulbs which are very good. Osram and Philips don't make competing fixtures so even if you like their bulbs, you still have to buy a fixture from somewhere to put them in.

[Mikael Couderc]

You said:
'I would hope that Osram or Philips could come up with something different or innovative'

Tell me about it...
Better yet: Tell them about it! (As I have for the past 10 years!)
I mean, they might well be the ones whom you'll buy the next gen of leds for your next-gen Coolights from!
But I agree, they certainly got the resources to experiment a bit (a lot!) and come up with better fluos and leds...

You said:
'Osram and Philips don't make competing fixtures'

True...Sorta...I'm sure I will teach you nothing by mentionning that they are two of the biggest manufacturers of HF ballasts...
I'm especially impressed by the stability and temps of Philips Dali line which you can also dim via DMX.
By the way, what are the ballasts used in the Coolights? (unless that's a secret :-) )

[Richard Andrewski]

5 years ago when I was designing our studio flos which was our first product, I looked at Osram and Philips but they didn't meet my criteria for universal voltage input. They probably still don't have universal voltage today. So for this reason, these makers are big in fixtures for other parts of the world, but they don't have a lot of market share for the USA.

In other words, we didn't want 110v or 220v only models like some manufacturers do, we though it would be better to go with a universal voltage input so they could work anywhere. Because of this I searched far and wide and tested many ballasts and found an off brand solution that I like very well and we continue to use that today. Same for our dimmable ballasts as well which we found about 3 years ago and continue to use them. They have been very reliable and will continue to stick with them. What brands those are are between Cool Lights customers and I ;-).

[Bill Davis]

While it's fun and all to talk about the THEORY behind this stuff... it's also instructive to make some PRACTICAL judgements.

The attached still capture is from 5dMkii shoot I did in Texas a couple of months ago. Since I had to fly in, my lighting kit was limited to two of Richard's Cool Lights 600s and one Cool Lights 250.

I own these in the 3200k versions, since most of my retail clients years ago re-lamped their stores for energy efficiency with modern fluorescent overheads that read closer to the old tungsten standard than daylight.

There is NO color correction or diffusion of any kind on the single 600 that I used for a key on the subject in order to open up his face under the brim of his hat. (Texas, after all!) You'll also see by the cast shadow that LED panels are inherently fairly soft to begin with.

So pull out and use all the meters and color measurement devices you like and hold fast to the idea that LEDs or Fluors are somehow "wrong" for video lighting. Personally, I'm just going to keep cranking out work with them. Because that's what I get paid for.

YMMV.

[Michael Panfeld]

Richard: thanks for sticking with this thread and sharing info. I took a bit of a strong approach in my posts, but I extracted quite a bit of info. So, I see that LEDs, fluoros, HMI, etc are best expressed as CCT rather than CT, due to the non-continuous nature of their emitted radiation across the spectrum.

As far as I can tell CCT is an approximation of what the CT would be, if the source was a black body radiator. I assume that, when you state your products' temperature, you are expressing it in CCT. Can you please confirm?

So my big question is, how accurate is the Sekonic's Digital mode in measuring CCT?

[Richard Andrewski]

Yes that is the crux of the issue. Anything measure in CCT would not be well handled on a color temperature meter because they simply (as of this time) are not that accurate for CCT sources (which are all discontinuous like LEDs, Flos and all metal halide).

I noticed that someone was saying that Minolta had a new meter that seemingly can measure CCT sources more accurately but its in the $3500 to $4000 range and I would have to see it to believe it. Plus you still won't get the nice printout of lumens, CRI, spectrum and all the other good things you get out of a sphere and its peripherals.

[Mikael Couderc]

Alright, Richard, I'll bite...
So much dedication to your cause deserves some acknowledgment, plus you've tempted me now :-)
So I'll give your new bi color 1200 (CL-LED1200) a try. I must say I like the concept behind it...

A couple of questions though:

-How well would you say the CT and G/M bias matches my Kino or Studioline fluo tubes when the 3000K and 10000K dimmers are set up so the output roughly matches 5600K. Specifically, can I make them match my fluos just by playing with the dimmers, or do I also need to add some + Magenta gel?

-I couldn't find the 'spot' version of these lights.... Got a direct link? Also, what's the spot angle (degree)?

-I wanna order a couple, to be delivered to France. How do I do that?

(Maybe we wanna carry on this discussion via private mails, unless you feel the answers might benefit other users...)

[Michael Panfeld]

Mikael: Since you are in the EU, perhaps you could give me your opinion on these:

THE LIGHT - The unique all in one Light

Richard: so does the Digital mode on the Sekonic approximate the CCT, falling short of the accuracy of higher-priced instruments? Or does it have no bearing at all on measuring CCT sources?

Thanks

[Richard Andrewski]

Mikael, I would suggest just sending an email to info@coollights.biz and we can continue there.

Michael, I think they do the best they can for CCT type sources in digital mode at least that is my understanding. Remember there is no "CCT" button on the meter so there is no way to tell it expressly this is a CCT type source you are measuring so given it is really a "CT" meter it is doing its best to interpret it as a "CT" type source. I often wondered if they did put a CCT button on there so you could tell it if they would be able to do a better job. Ultimately we'd have to ask them about that and why they didn't do it that way.

[Mikael Couderc]

Hi Michael,
I remember seing them (or something similar) briefly on a show in Spain a few months back. I was running out of time and didn't get enough time to go check them out, although I really wanted to.
Thank you for reminding me of them!
I've just spoken on the phone with their sales rep in southern france and I'm planning on demoing their products within the next few days (they're based less than an hour away from where I live!)
I'll report back here.

In the meantime, their site looks very informative with regards to the technology used in their fixtures.
One person I'm sure looking forward to hearing from is Coolights' Richard himself, as he's clearly demonstrated he's very knowledgeable and he'll sure point out any pros and cons of their technology vs the one in his own fixtures...

[Tom Morrow]

Traditional color meters only have three photocells, with responses roughly matching the film or human eye sensitivities to R, G, B. That works great if you are working with light that doesn't have the peaks and valleys that LED/flo show for spectra.

But color meters designed for discontinous sources have more "photocells" which are sensitive to different parts of the spectra. The more the better; one I researched a decade ago designed for calibrating LCD projectors had nine channels; the better ones today must have 20 or more channels. The more channels the more resolution and the more you can approach "what film sees" or "what the eyes see".

[Bob Grant]

Originally Posted by Richard Andrewski

As far as the other bulbs mentioned, I would hope that Osram or Philips could come up with something different or innovative. How large of companies are they? How many employees do they allocate to R&D? What is their revenue every year? Bulbs are their main specialization or a very big part of the company in any case. My main specialization is fixtures for film and television and yes we do have some bulbs which are very good. Osram and Philips don't make competing fixtures so even if you like their bulbs, you still have to buy a fixture from somewhere to put them in.

I have had a discussion with Osram on this topic a few years back. Their high CRI tubes are only available in 36W, why not in make them as part of their Studioline range? The answer was that the market for the existing 55W Studioline tubes equates to less than one hour of the factories production time. To make another variant of the same tube is simply not economic.

I've run into much the same hurdle with their T5 tubes. I'm installing lighting for an office / showroom and wanted the "cool daylight" tubes in "950", Osram list them but had zero interest in importing less than 1,000 units and I only needed 100. Locally Osram cut back their staff dramatically recently and the lady who was our champion in getting our hands on the fluro tubes for film and television is gone. It all comes down to economics, even within our small market segment the number of people who care enough to create a viable demand is just too small.

A couple of bits of information I did pickup from when Osram locally were more focussed on our needs. The higher CRI tubes seem to contain more phosphors, I think 5 instead of 3. One European manufacturer of lighting instruments claims to have a supply of 55W tubes made by Osram with 5 phosphors. We've tried a set and really could not see a difference that'd justify the higher price. If and when I do get some good test gear I'll revist these.
The green spike fades with use of the tube. The tube needs to burn in for around 200 hours.