Hi guys,
I understand that Lumileds has state of the art testing equipment that is continually checked for calibration. Hopefully the new binning criteria will rank the LED's in a manner that agrees with what we see. Recently, I have been working with some R2 1Ws as well as some V2 5W's and W4 5W's. The W4's have a greenish tint whereas the 2 bin LED's don't. I was told by a friend that these W4's actually measure out with a higher color temperature in an integrating sphere than say the V2's.
When do we see the tint? I propose that we see the tint when we view the light being reflected off of a near white surface. Well we *really* want this light to be full spectrum which we know LED's really aren't. I was comparing an A2 which has an obvious *warmer* tint to it than a KL4 I have which is white with perhaps a hint of blue tint to it. When looking at various colored objects with both lights, I noticed that the A2 returned a less biased image with some colors; especially red. Some red tool boxes were obviously red under the KL4 but they were dark, relative to the other objects caught in the beam. With the A2, the tool boxes were a much brighter red and in keeping with their color under full spectrum light.
What's my point? Well I think with esthetics aside, we want white light as we assume that white light is full spectrum and it will give us full color information when used for illumination. Is it possible that the "ice" white colored LED's are less capable of full spectrum return? I think we should consider using some type of color wheel as a target for our beam analysis and consider these results as well as information returned from a white surface. I propose that a light with its color balance off white might still be more capable of full color rendition than a light that is closer to white in its balance. It has been commented that these Luxeons which are off white are perceived as white when there is an absence of other light sources. Perhaps *gaps* in the spectrum may be more important than the total balance perceived?
As to the subject: "Is the L4 getting better?", I think it's a safe bet that the gaskets are now part of the assembly and further, that SF gets and uses only premium bin ranks provided by Lumileds. These ranks are determined by sophisticated measuring equipment and not the human eye. Hopefully with the new binning structure, machine and eye will be more in agreement.
- Don
