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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Trucolor HS

We had an advance look at the Trucolor light and the technology behind it at our SMPTE meeting in NYC last September (Abel hosted).

Was very impressed. Personally, I'm looking forward to adding this to my inventory - expect that it will play a central role in my kit of lighting tools.


Should also mention - take a look at the Trucolor Foton.
AC & DC models, 30 W = 1000 lumens, lightweight, dimmable (no color shift), excellent spectral output and the claim is waterproof - will turn into a must-have for all location work.
(PRG was displaying it at last fall's East Coast Cinegear - almost missed it, glad I didn't)
 
Brian F Kobylarz said:
We had an advance look at the Trucolor light and the technology behind it at our SMPTE meeting in NYC last September (Abel hosted).

Was very impressed. Personally, I'm looking forward to adding this to my inventory - expect that it will play a central role in my kit of lighting tools.


Should also mention - take a look at the Trucolor Foton.
AC & DC models, 30 W = 1000 lumens, lightweight, dimmable (no color shift) and the claim is waterproof - will turn into a must-have for all location work.
Click to expand...


Yes the Foton is cool too. I wonder why there is no Daylight version???
 
I tried to use a couple of these last week, one didn't work and the other kept cutting out. I think it was operator error but didn't have time to investigate. I think it was traced to the door that hold the filters not being securely in place. It was also very hot in the location which may have had something to do with it. I'll give them another try when I'm not on a shoot. Great output, though and very useful for Highspeed shooting.
 
Shane Kelly said:
I tried to use a couple of these last week, one didn't work and the other kept cutting out. I think it was operator error but didn't have time to investigate. I think it was traced to the door that hold the filters not being securely in place. It was also very hot in the location which may have had something to do with it. I'll give them another try when I'm not on a shoot. Great output, though and very useful for Highspeed shooting.
Click to expand...

I believe there is a safety mechanism now which doesn't let you operate if the filter is not properly on. Perhaps there's crazy UV omitted without the filter. Who knows. I look forward to more reviews. Thanks Shane.
 
Bob Gundu said:
I believe there is a safety mechanism now which doesn't let you operate if the filter is not properly on. Perhaps there's crazy UV omitted without the filter. Who knows. I look forward to more reviews. Thanks Shane.
Click to expand...

I think that that was probably the case.
 
Yes, there's a safety switch in there for this. It's not true UV but since the frequency band of the emitters is so narrow, one does not realize at first how powerful they are and can hurt one's eyes if looking at them directly without the phosphor panel in place. Similar to a laser; you'd don't realize how powerful it is until ouch!

The Trucolor Foton was originally developed for theatrical and installation work, and PRG's research found that overwhelmingly tungsten balance was preferred. In most cases the light is replacing a tungsten fixture.

The Trucolor HS has interchangeable phosphor panels, and they are available in a variety of color temperatures. I really like the 2700K panels which are meant to match well with household tungsten practicals. I've been on so many sets where the lights are all dimmed 15-20% to get the added warmth. I believe the old Oprah set was entirely lit this way. Fabulous fesh tones.
 
Bob Gundu said:
Has anyone tried these yet? I thought there would have been more testimonials by now.
Click to expand...

What more user review do you need than Shane Kelley’s below:

Shane Kelly said:
I tried to use a couple of these last week, one didn't work and the other kept cutting out. I think it was operator error but didn't have time to investigate. I think it was traced to the door that hold the filters not being securely in place. It was also very hot in the location which may have had something to do with it. ...
Click to expand...

The problem can’t have anything to do with the door. In the demo video in the OP they open the door to swap Phosphor panels and the light doesn’t shut off. Clearly there is no door safety switch like in an HMI. It most likely has to do with the “very hot location.” LED lights, like the Trucolor HS, that use passive heat sinks to regulate the operating temperature of their LED emitters are very sensitive to ambient temperature for reliable operation. This is why Arri has designed into the passive cooling model of their L7 LED Fresnels a fan that comes on automatically so that they don’t get too hot. Since thermal management is critical to the reliable operation of LEDs, I suspect that the problem had to do with the fact that the location was very hot. Where just about every shooting location I have ever worked on gets warm (unless it is specifically designed for that purpose like studios), I wouldn’t stake my reputation on such finicky lights that clearly have issues with thermal management.

Peter Berger
 
Thanks for the insight into LED's. It's been a couple of months since these have come out and haven't heard much since they've won numerous awards.

Peter Berger said:
What more user review do you need than Shane Kelley’s below:



The problem can’t have anything to do with the door. In the demo video in the OP they open the door to swap Phosphor panels and the light doesn’t shut off. Clearly there is no door safety switch like in an HMI. It most likely has to do with the “very hot location.” LED lights, like the Trucolor HS, that use passive heat sinks to regulate the operating temperature of their LED emitters are very sensitive to ambient temperature for reliable operation. This is why Arri has designed into the passive cooling model of their L7 LED Fresnels a fan that comes on automatically so that they don’t get too hot. Since thermal management is critical to the reliable operation of LEDs, I suspect that the problem had to do with the fact that the location was very hot. Where just about every shooting location I have ever worked on gets warm (unless it is specifically designed for that purpose like studios), I wouldn’t stake my reputation on such finicky lights that clearly have issues with thermal management.

Peter Berger
Click to expand...
 
Played with the one they have on display at the source shop today - I'll tell you what I really think on set next week Bob...
 
Just shot a review for this light that will soon be available on the ACS website and FXGuide's website. I will post the details when we have it up. In summary a great light with a wonderful quality. A few caveats but at the price point good value. Most importantly it is a clean continuous source that requires no correction gels and thats one of its real strengths that you change out the phosphor panel to change colour temp with no loss of output. The pure green phosphor panel is a real win for chroma shoots although we did not test it
 
Tom Gleeson said:
Just shot a review for this light that will soon be available on the ACS website and FXGuide's website. I will post the details when we have it up. In summary a great light with a wonderful quality. A few caveats but at the price point good value. Most importantly it is a clean continuous source that requires no correction gels and thats one of its real strengths that you change out the phosphor panel to change colour temp with no loss of output. The pure green phosphor panel is a real win for chroma shoots although we did not test it
Click to expand...



Thanks Tom. I look forward to the review.
 
Tom Gleeson said:
… it is a clean continuous source that requires no correction gels and thats one of its real strengths that you change out the phosphor panel to change colour temp with no loss of output.
Click to expand...


I would not call the output of the HS a “continuous source”. If you look at the Spectral Distribution graphs for the HS on PRG’s website you will see that it still has peaks and valleys in its’ output and in no way resembles that of a true black body radiator like a Tungsten filament. It also suffers the inherent limitations of all Phospher White LEDs using Remote Phospher Technology to generate colors with longer wavelengths.

The inherent limitation to the “Stokes shift” process by which a portion of a “pump” color is transformed from shorter wavelengths to longer wavelengths using Phosphers (remote or not) is that there is a tradeoff between lumen output and warmer color temperatures. The HS clearly suffers from these limitations. Its’ output with the 3200K panel is less than that with the 5600K panel and its’ spectral distribution is more discontinuous. While the HS (with the 3200K panel) appears to generate more light in the medium blue-cyan-turquoise range from about 465-510nm than the typical 3200K Phosphor White LED, it still drops out appreciably; and its’ long-wavelength cutoff is still at about 625 nm where a tungsten filament continues to generate light all the way out. Since these long wavelength colors are critical to rendering a realistic flesh-tone, talent has a tendency to look pale under the HS compared to how they look under a tungsten instrument.

Another problem related to the discontinuous output of the HS is that standard color correction gels like CTOs have unexpected and undesirable effects on them. A good example of this is what happens when you try to warm them up further with a Full CTO gel. Full CTO is designed to pass extra green (there is a bump in the spectral transmission curve of Full CTO in the green portion of the spectrum) and so it creates, given the amount of green inherent in the HS to begin with, a disproportionate amount of green - creating an overall green cast that you don’t get using the same gel on a tungsten instrument. DP Michael Morian recently conducted some camera tests that clearly demonstrates the unexpected and undesirable consequences of using CTO gels on LED light sources for which they were not designed. You can see the results for yourself on his website at http://talltalepictures.com/blog/2011/12/06/are-led-1x1-panels-ready-for-prime-time/.

Peter Berger
 
Peter is correct in saying that the light is not a continuous source but I would not discount the light because of this. It's output is in fact bright and very good. I shot my own tests with Macbeth charts and with skintones and was very pleased with the results. You see only a tiny drop in saturation in the skintones but hard to spot with your eye.

I suspect that the use of Color correction gels could see some strange responses but one advantage of this light is that the removable panels producing different color temperatures mean you are unlikely to need gels with the added advantage of no light loss. We measured only a tenth of a spot drop in output from 5600 to 3200. Not to mention the ability to produce a pure green for chroma key work.

My main criticism is that the light requires a large 6kg ballast limiting its appeal if you are doing a lot of run and gun.
 
@Tom : Also looking forward to your review. Did you get a chance to compare this HS with the FOTON side by side to see if the Fotons reds rendered flesh tones better?

@Peter: I think you highlight a good point that existing Gels are not suitable for LED spectral dristribution.

+) One thing that confused me on the Macbeth/R12 for the LightPanels 1x1 ... was why is the score '0'?
http://www.prgtrucolor.com/node/26

+) When PRG (& Intermarix Corportation) have the Remote Phospher recipe to output Turquoise, they will be able to improve the balance of the 5600k (and other high K) lighting - and a new sheets 'swapped in'.
http://www.prgtrucolor.com/sites/default/files/docs/hs-cut-sheet-august.pdf

+) Use of a large Remote Phosphor sheet at a distance from the LED source (unlike White light LEDs) reduces the temperature per unit area. This increases the efficiency of the light output (and longevity of the panel). There is also a much tighter tolerance due to the thickness of the PRG panel.

+) Even though there is a reduction in light output at higher K - these lights are still vastly more efficient than Tungsten.

+) The HS / FOTON are near continuous spectrum - but virtually continuous output (no flicker)

+) What I would really like to see is more lights that use Light Emmiting Plasma (LEP) filaments. These seems to be full spectrum - and even more efficient than the current crop of high efficiency LEDs.
http://www.luxim.com/technology/features/quality-of-light

AJ
 
Tom Gleeson said:
I suspect that the use of Color correction gels could see some strange responses but one advantage of this light is that the removable panels producing different color temperatures mean you are unlikely to need gels with the added advantage of no light loss.
Click to expand...

Unless PRG plans to introduce panels for every grade of CTO, CTS, CTB, not to mention every theatrical gel from Lee, Rosco, and GAM, then the color pallet of this light is very limited and IMO very boring. For example, where there is an appreciable difference between half CTO and half CTS, being restricted to a 4300K panel is very limiting. To help fix this problem in the theatrical world LEE Filters has launched a new range of LED Filters specifically designed to produce a visual color match to existing popular Lee colors (105 Orange, 126 Mauve 106 Red) on Tungsten (3200K) sources when used on Cool White LEDs. The drawback to the Lee LED gels is that they are calibrated to match a specific LED source (Cool White Remote Phosphor LEDS – the type almost universally used in theatrical lighting) and the number of colors are very limited. Perhaps, Rosco, Lee, or Gam, will someday come up with as wide array of gels calibrated for LEDs like we presently have for tungsten sources, but I doubt it will be any time soon given that there is no standard spectral output to LEDs used in motion picture lighting applications. I would suggest that anyone interested in this topic visit LEE’s website (http://www.leefilters.com/lighting/led-02.html#colorlist) and watch the demonstration video.

Peter Berger
 
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