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High CRI light strips

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mkiker2089

Joined: Feb 26 2015
Posts: 5


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Post Thu Feb 26, 2015 10:56 am

I wanted to use light strips at about 1 meter in length for a display case. The problem I'm running into is that most strips are very poor regarding color rendering. Does anyone know of some decent CRI strips that are available? I'd rather they didn't cost a fortune and I need two strips of about a meter so no 16m rolls please.
Tdawgthegreatest

Joined: Jul 22 2007
Posts: 5093
Location: Florence, Oregon


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Post Thu Feb 26, 2015 6:35 pm

Most LED's (in the "cool white" 4000-5000k range) have a 80+% CRI which is higher than flourescents (cheap ones are 50%, more expensive are around 90%). So basically I believe Ozniums Ribbon LED Strips in cool white (https://www.oznium.com/flexible-led-strips/led-ribbon) would be fine. So you are looking at about $35 per 3 foot (little under a meter) strip.
mkiker2089

Joined: Feb 26 2015
Posts: 5


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Post Thu Feb 26, 2015 7:05 pm

Ok, I wrote to Oznium about it earlier and the onctact wasn't aware LEDs could be measured in CRI. She promised to contact her manager about it. It may be a few days for a response from them.

Suberbright LEDs said all their strips are 72 except on which is around 9000kelvin (to blue for my tastes) and it's only 85. They declined to answer any other questions.

I wondered what it would be like to wire up an RGB and have all the colors on. I've done that with cheap Ikea lights and it looks decent. I don't have equipment to test the CRI though. I've read that usually gets you to or just past 80.

Then there's the old trick with fl. lights where you would combine a cool and warm white because the different phosphors used to get each shade complemented each other. I can't find any info saying it still works but it's possible.
mkiker2089

Joined: Feb 26 2015
Posts: 5


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Post Thu Feb 26, 2015 7:25 pm

I may end up ordering the 12v blue chip version of this My concern there is how to connect them after I cut them to size. I'd spend only a little more but I don't want to have to solder end on them.

I'm still hoping someone at Oznium pulls a rabbit out of their hat and can surprise me.
mkiker2089

Joined: Feb 26 2015
Posts: 5


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Post Fri Feb 27, 2015 1:59 pm

Well, my response from Oznium was less than I hoped for. The short answer is at least 70, probably no higher than 80. That's ok, but not good for showing off collectibles. The long answer

>> Do you offer any high cri strips?


How high CRI does customer require?
Generally most LED lights do not have a CRI higher than 90. Normal white LEDs have around 70 to 80. We could source the LEDs with higher CRI like 85 but the cost of each LED would be at least a couple times higher.




>> Can I wire an RGB unit to emit all colors? If so would it be a good CRI?


No. The RGB LEDs would not have a good CRI.





To determine the CRI rating, testing 8 standard color samples R1-R8 (& may also include 7 additional samples R9-R15) are used as reference.
The lights spectrum from RGB LEDs could be made similar to the fluorescent lamp in its %u201Cspikiness%u201D but those particular wavelengths do not perform like incandescents on those sample CRI colors. So the CRI of RGB LEDs is generally low, around 30-40







>> Do you know if combining different white temperatures would improve CRI? I know that was the thing to do with fl. lights but LED is totally different to me.


Yes. Combining different white color temperatures LEDs would slightly improve CRI. The amounts of CRI improvement actually depends. It could be 0.5 or sometimes 3 or 4 difference.
dasdsa

Joined: May 14 2015
Posts: 1


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Post Tue May 26, 2015 8:27 pm

What is THE CRI you will need?Mostly, 80-85 should be not bad.
corvettecrazy

Joined: Dec 17 2003
Posts: 4357
Location: moved (twice)


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Post Thu May 28, 2015 5:50 pm

This really depends what you are trying to light. Mostly in terms of what the colors of the items you are trying to illuminate.

Color science is a deep field and is not very well understood by many. Even less is understood about how different colors impact the human body. (Although we are getting there) If you begin to read about it you will soon understand that CRI is fairly full of **** and not a great metric for judging light quality. Sadly it is what people have began to understand and changing to a new metric would be like trying to covert the US to the metric system. (Even if it would be way smarter)

Many LED's you will find are 60+ or 70+ CRI. There are 2 main reasons for this. The first is output. To create a higher CRI LED manufacturers generally have to use more red phosphor. This phosphor is less efficient than the phosphors that are used for the green and blue spectrum. Secondly, all phosphor is expensive but red is more expensive than the rest.

To expand more on item one, using rough numbers, there is approximately a 7-10% drop in output if you compare 90+ to 80+ CRI LED's. Another 7-10% drop going from 80 to 70. This means to get the same output on an LED you will need to increase the die size within the LED as the CRI increases. Dies are one of the more expensive parts of the cheap (generally) **** LED's used in LED strips.

Is it possible to get 90+ CRI LED strips yes, absolutely. Do you need it, probably not, but this goes back to the first 2 things I wrote.

If you are heart set on higher CRI LED strips I would suggest you stop looking at LED strips coming from China and start looking at products made by the top 10 LED manufactures in the world. Future Electronics carries a wide variety of LED strips made by Philips. They do make 80+ and 90+ CRI LED strips. And yes they will cost you more. You will also need to use a real LED driver vs a 12v power supply that normally powers the LED strips with a current limiting resistor. But hey, you get what you pay for. You can also web search "90 CRI LED strip" and I bet you will find products.

Welcome to the world of real LED's, as opposed to the "plug me into 12v" world.

Post Script Rant: CRI is not a damn percentage. Never was, never will be. It does not have units, deal with it.
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