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5600 Kelvin on RGBAW LED?

luddite111@...
 

I have a video shoot on a soundstage in late July that requires me to light the same set with 2 different looks. One will be UV light, the other 5600 Kelvin daylight.

I have found a LED par fixture available at a local theatrical rental house called Chauvet Colordash Hex 12 RGBAW+UV. I was wondering if anyone knows how to get 5600 Kelvin on a theatrical Led fixture? I am trying to avoid rigging 2 sets of lights to get the 2 looks.

I have seen specs on these theatrical lights that say 2,800-10,000 Kelvin is possible but when I read the manual I don't see how to set that - there is no Kelvin setting in the menu.

I will also have a few Skypanel S60 on set for the 5600 K scene.
It doesn't have to be perfect but would like to match the S60's.

Thanks!

Nick Anthony
Gaffer
SF Bay Area

Art Adams
 

  1. Find a monitor with an RGB parade waveform monitor.
  2. White balance your camera to a Skypanel (red, green and blue peaks should be at the same height in RGB parade). Expose your white reference more for middle gray than white (40-50%) as the white balance will be more accurate.
  3. Turn off the Skypanel and then light the white reference to the same level with the RGBW light. Without touching the camera's white balance, manipulate that fixture's color until it is white balanced in the same way (red, green and blue peaks align in RGB parade).

You should now have a metameric match to your Skypanel.

--
Art Adams
Director of Photography
San Francisco Bay Area

Marque DeWinter
 

Chavet, and theatrical lights in general aren’t made to the same specs as film lighting. Do a test. They often aren’t very accurate with color rendition (including color dashes) and the RGB is usually hexadecimal so 1-255 for each channel.
(My fiancée is a theatrical electrician and so when I help her out we often have these)

~Marque

Christos Oscar Kambiselis
 

You can also use a color meter, like the Sekonic C-700 and match the two lights, from the fixture manual it seemed there is a white balance setting where you can add R,G or B while the white led is on.

Christos Oscar Kambiselis 
DoP
Lynx Pictures 
Finland 

On Tue, Jun 26, 2018, 16:49 Marque DeWinter <redcameraop@...> wrote:
Chavet, and theatrical lights in general aren’t made to the same specs as film lighting. Do a test. They often aren’t very accurate with color rendition (including color dashes) and the RGB is usually hexadecimal so 1-255 for each channel.
(My fiancée is a theatrical electrician and so when I help her out we often have these)

~Marque

Steve Oakley
 

Be wary of flicker with LED stage lighting. the cheap ones will flicker because they seem to run at 120 / 60hz PWM for dimming. They may be ok full up, but at 50% dim not so good. something to be alert for.

Steve Oakley
DP / Editor / Colorist / VFX Artist
Madison & Milwaukee WI
920 544 2230

On Jun 26, 2018, at 7:37 AM, Marque DeWinter <redcameraop@...> wrote:

Chavet, and theatrical lights in general aren’t made to the same specs as film lighting. Do a test. They often aren’t very accurate with color rendition (including color dashes) and the RGB is usually hexadecimal so 1-255 for each channel.
(My fiancée is a theatrical electrician and so when I help her out we often have these)

~Marque
_._,_._,_

Art Adams
 

Color meters don't work well on LED lights. The C-700 might work slightly better than most, but none of them work perfectly and most fail with LEDs.

A while back Adam Wilt and I lined up a bunch of color meters on a table and looked at how they responded to different kinds of light. At 3200K and 5500K they all agreed within a hundred or two hundred degrees Kelvin. In between, they didn't come close to agreeing. The C-700 may have been the only correct one, but I have no idea if that was the case. (The middle-ground light was full spectrum ambient daylight through a window.)

Ultimately a camera is a spectrometer that samples three overlapping portions of the spectrum. That means that if the C-700 does really sample the entire spectrum contiguously, as it claims, it's not seeing the world the way a camera does—so we have no idea if the camera would see things in the same way. The meter may indicate a match between two LED fixtures, but as the camera works differently—and actually attempts to make a color image out of its samples instead of estimating the overall color of a light source—it may not see the same thing.

A camera is all about color and contrast. A meter is all about math. The two things do not always line up the way they should.

The safest thing is to match the lights on set using the camera, as previously described. White balance the camera to the reference fixture, then match the reference light's level with the white phosphor and look for the gaps. Bring up red and green, and blue if necessary, to fill in the metameric gaps.

As mentioned, though, the spectral response will likely suck, as any light capable of pure colors must use narrow band LEDs, and while those are great for color effects they are not great for flesh tone. You should expect them not to look good on people, even if you get them to match the Skypanels.

--
Art Adams
Director of Photography
San Francisco Bay Area

Dave Lowing
 

Very well said Adam.  You talk directly to my issues with all meters today.  Whether it’s color or light quantity, the only light meter I trust anymore is the specific camera and monitor being used on the day.  



David Lowing
President/Gaffer  
Lowing Light & Grip
Office  1-888-530-7440
Cell  1-616-437-4075
Fax  616-249-8947
iphone docdav1@...






On Jun 26, 2018, at 2:47 PM, Art Adams <art.cml.only@...> wrote:

Color meters don't work well on LED lights. The C-700 might work slightly better than most, but none of them work perfectly and most fail with LEDs.

A while back Adam Wilt and I lined up a bunch of color meters on a table and looked at how they responded to different kinds of light. At 3200K and 5500K they all agreed within a hundred or two hundred degrees Kelvin. In between, they didn't come close to agreeing. The C-700 may have been the only correct one, but I have no idea if that was the case. (The middle-ground light was full spectrum ambient daylight through a window.)

Ultimately a camera is a spectrometer that samples three overlapping portions of the spectrum. That means that if the C-700 does really sample the entire spectrum contiguously, as it claims, it's not seeing the world the way a camera does—so we have no idea if the camera would see things in the same way. The meter may indicate a match between two LED fixtures, but as the camera works differently—and actually attempts to make a color image out of its samples instead of estimating the overall color of a light source—it may not see the same thing.

A camera is all about color and contrast. A meter is all about math. The two things do not always line up the way they should.

The safest thing is to match the lights on set using the camera, as previously described. White balance the camera to the reference fixture, then match the reference light's level with the white phosphor and look for the gaps. Bring up red and green, and blue if necessary, to fill in the metameric gaps.

As mentioned, though, the spectral response will likely suck, as any light capable of pure colors must use narrow band LEDs, and while those are great for color effects they are not great for flesh tone. You should expect them not to look good on people, even if you get them to match the Skypanels.

--
Art Adams
Director of Photography
San Francisco Bay Area

Mark L
 

Hi Nick,

 

Not sure if this will help you with your situation.

 

Depending on the LEDs you are using, check out proficientlight.com.au to explain what they are and can do

 

They are a handy thing to have in a Gaffers kit for the price if using LEDs

 

Mark Levey

Gaffer

Australia

 

Sent from Mail for Windows 10

 


From: cml-lighting@... <cml-lighting@...> on behalf of luddite111 via Cml.News <luddite111=yahoo.com@...>
Sent: Tuesday, June 26, 2018 2:19:25 PM
To: cml-lighting@...
Subject: [cml-lighting] 5600 Kelvin on RGBAW LED?
 
I have a video shoot on a soundstage in late July that requires me to light the same set with 2 different looks. One will be UV light, the other 5600 Kelvin daylight.

I have found a LED par fixture available at a local theatrical rental house called Chauvet Colordash Hex 12 RGBAW+UV. I was wondering if anyone knows how to get 5600 Kelvin on a theatrical Led fixture? I am trying to avoid rigging 2 sets of lights to get the 2 looks.

I have seen specs on these theatrical lights that say 2,800-10,000 Kelvin is possible but when I read the manual I don't see how to set that - there is no Kelvin setting in the menu.

I will also have a few Skypanel S60 on set for the 5600 K scene.
It doesn't have to be perfect but would like to match the S60's.

Thanks!

Nick Anthony
Gaffer
SF Bay Area

leanne
 

hi, Nick, general led panel light can be 5600k, first 5600 Kelvin mean the color temperature, general are 3200k-5600k, also bi-color and RGBW led can be 2800k-10000k, but it also depends on the manufacturer. check mhgled.com to see and Compare lights with different color temperature.