I would like to focus this thread on discussions more in general and of the rambling and brain storming fashion that we sometimes enjoy here. I'll set a little background and then leave the thread open to go where it will.
There have been many threads and discussions already about color rendering, tints and the ability of the various lights to illuminate colors and their relative intensities. Initially when LED's were weak, there was much said on the LED VS Incan comparisons. Now that LED's are putting out significantly more lumens, for many the issues have become less significant if at all.
My house now is essentially all LED in illumination and it has been great for the most part. I did discover that in the bathrooms at least, I needed to add some red LED's to bring the skin tones and colors closer to realistic or what you would see under natural light. Another area I found I needed to improve was in the cooking area where the meat preparation was difficult without some better red rendering. Instead of using red LED's in addition to the typical high power LED's I have been working with, I opted to use a LED I have been silent about*, namely a Nichia 083 High CRI LED. Above my stove, I have a string of these:
There were two 35 watt incans which were replaced by these Nichias driven by a Xitanium driver.
* I feel bad about keeping silent so long on these Nichia High CRI LED's because my motivation has been purely selfish in doing so and not in the spirit of moving the "art" forward as quickly as our community can. I told myself that as soon as I had a complete first article light in hand I would spill the beans on this LED. I completed a first article SunDrop today:
More on the SunDrop in a new thread devoted to it.
Back to High CRI.....
I think for the most part, color rendering is adequate with what we have on hand now and with enough lumens, one can overcome short comings in certain wave bands. However, there are specific applications and times when better or "full color" is important and desired if not required. Further it is my suspicion that typically this need for good color rendition is in flood applications where you don't want radical gradations in intensity across the field as would be the case of a collimated beam like from a reflector.
These Nichia 083 High CRI LED's have a different phosphor in them and unfortunately this phosphor inherently cuts down on the flux similar to how the warmer tint LED's suffer in lumen reduction. However, I have found in talking about CRI and warm tints with the LED people that there are bins for warm and neutral white that are no better in CRI than the higher color temp bins and then in addition, there are bins and phosphors where CRI itself is of primary focus. I have sampled some Seoul LED's which report to approach 90 CRI a. The Nichias are ranked in the mid 90's.
With no idea of true accuracy or level of possible error, I offer a couple spectrums I captured with my spectrometer and integrating sphere. The first is with a sample 083 High CRI and a Cree XR-E that I had handy:
I was impressed enough with some proto lights I built and walked around with to bite the bullet and order a reel of these Nichias (1400 pieces!) along with modifying a MCPCB that was in the works so that it would be host to both the Dragon and Nichia 083 LED. In the spectrum below, one of the 1400 production pieces in the SunDrop is compared to today's noon sun here on Maui:
You will notice that in the case of this sample, the blue spike is not as high as the max or peak wavelength which is pretty close to the sun sample. Again, I don't consider myself expert or even proficient with the spectrometer and its software so these graphs can't be taken as rock solid. They do support what my take and perception has been in actually using the LED's.
I also have a CreeBar on Makita battery that I mentioned in another thread a while back:
I have been using this light for fill in in many of the recent photos and there may be some advantages for high CRI sources in photography as well.