LED Bi-Color in 3200K does need minus green correction filter? at DVinfo.net

Alex Muller · October 29th, 2010, 01:19 AM

Hi!

I'm about to purchase a set of LED Panels 1x1 from Cinelight vendor and I would like to know if a LED Bi-Color set in 3200K would required minus green correction filter to remove the nasty green spike.
I know that the so claimed 5600K led's need some degree of minus green correction filter but how about the 3200K?
Does the 3200K led's suffer from green spike?

Thank you!
Alex

Robin Lambert · October 29th, 2010, 01:46 AM

Since they proudly give a CRI of 85 for their straight daylight LEDs (which is actually quite poor, about the same as domestic fluorescents) but don't give any info on the CRI of their tungsten LEDs, I would suggest that you will need a bit of minus green.

Alex Muller · October 29th, 2010, 11:13 AM

Under key feature they mention "-ultra-efficient LED technology with high CRI level (90RA)."
CRI 85 is for the DayLED 600 led panel. All LED 1x1 models are mentioned with CRI 90.

I'm wondering how a minus green 1/4 over a tungsten balanced source will affect the color temperature ..

Robin Lambert · October 30th, 2010, 02:23 AM

Just a warning, a CRI number under the RA system is not the same as the original CRI system.

Some LED and fluorescent tube manufacturers claimed that the original CRI system didn't take into account the nature of their products and so adopted another system with different colour charts which was better for sources with spiky outputs. So a CRI number with the RA system is not the same as the "standard" CRI.

In my experience a 249 quarter minus green will have hardly any effect on the colour temperature and measurements show that it takes a 3200k tungsten down to >3100k, a mired value of about -10 to -20, less than a one eighth CTO, in other words, hardly noticeable.

Reg Carter · October 30th, 2010, 07:02 AM

I have a quick question and though it diverges from the main question, I am hoping one of you can confirm my suspicion. I have warm cards in my kit and the minus green card is, in fact, green. I recently purchased an LED light set that includes a minus green gel that is colored magenta. My question is, do I white balance with the LED light before adding the magenta gel, since it colors a white card slightly magenta and I would assume make the camera see magenta as white, whereas my minus green warm card makes the camera see green as white?
Thanks for any clarification.
Reg

Robin Lambert · October 30th, 2010, 07:18 AM

If you white balance on a green card it has the same effect as putting a magenta filter on the camera lens.

So, if you white balance on the "minus green" card, the whole scene will take on a magenta hue. If you put your magenta filter over the light source, then only that light will be "corrected".

If your LED is the only source of light, I would switch it on, point it at a white card, or piece of paper and do a white balance. If there were other sources then I would put the magenta filter on the LED to match it to the other lights.

October 29th, 2010, 01:19 AM	#1
Alex Muller Tourist Join Date: Oct 2010 Location: Hungary Posts: 3	LED Bi-Color in 3200K does need minus green correction filter? Hi! I'm about to purchase a set of LED Panels 1x1 from Cinelight vendor and I would like to know if a LED Bi-Color set in 3200K would required minus green correction filter to remove the nasty green spike. I know that the so claimed 5600K led's need some degree of minus green correction filter but how about the 3200K? Does the 3200K led's suffer from green spike? Thank you! Alex

October 30th, 2010, 07:02 AM	#5
Reg Carter New Boot Join Date: Oct 2005 Posts: 22	Minus Green Filtering with LED I have a quick question and though it diverges from the main question, I am hoping one of you can confirm my suspicion. I have warm cards in my kit and the minus green card is, in fact, green. I recently purchased an LED light set that includes a minus green gel that is colored magenta. My question is, do I white balance with the LED light before adding the magenta gel, since it colors a white card slightly magenta and I would assume make the camera see magenta as white, whereas my minus green warm card makes the camera see green as white? Thanks for any clarification. Reg

October 29th, 2010, 01:46 AM	#2
Robin Lambert Regular Crew Join Date: Aug 2008 Location: London Posts: 70	Since they proudly give a CRI of 85 for their straight daylight LEDs (which is actually quite poor, about the same as domestic fluorescents) but don't give any info on the CRI of their tungsten LEDs, I would suggest that you will need a bit of minus green.

October 29th, 2010, 11:13 AM	#3
Alex Muller Tourist Join Date: Oct 2010 Location: Hungary Posts: 3	Under key feature they mention "-ultra-efficient LED technology with high CRI level (90RA)." CRI 85 is for the DayLED 600 led panel. All LED 1x1 models are mentioned with CRI 90. I'm wondering how a minus green 1/4 over a tungsten balanced source will affect the color temperature ..

October 30th, 2010, 02:23 AM	#4
Robin Lambert Regular Crew Join Date: Aug 2008 Location: London Posts: 70	Just a warning, a CRI number under the RA system is not the same as the original CRI system. Some LED and fluorescent tube manufacturers claimed that the original CRI system didn't take into account the nature of their products and so adopted another system with different colour charts which was better for sources with spiky outputs. So a CRI number with the RA system is not the same as the "standard" CRI. In my experience a 249 quarter minus green will have hardly any effect on the colour temperature and measurements show that it takes a 3200k tungsten down to >3100k, a mired value of about -10 to -20, less than a one eighth CTO, in other words, hardly noticeable.

October 30th, 2010, 07:18 AM	#6
Robin Lambert Regular Crew Join Date: Aug 2008 Location: London Posts: 70	If you white balance on a green card it has the same effect as putting a magenta filter on the camera lens. So, if you white balance on the "minus green" card, the whole scene will take on a magenta hue. If you put your magenta filter over the light source, then only that light will be "corrected". If your LED is the only source of light, I would switch it on, point it at a white card, or piece of paper and do a white balance. If there were other sources then I would put the magenta filter on the LED to match it to the other lights.