I admit it, I am a geek when it comes to LED's and LED lighting. The fluorescent under counter lighting that came with my hose wasn't cutting it. Time for an upgrade! With a background in physics and surgical lighting, I knew I needed a good Color Temperature and Color Rendering Index (CRI). So what are Color Temperature and Color Rendering Index? They are two measures of what light looks like and how it makes things look when it illuminates them. Color Temperature can be read about here, and Color Rendering Index here. Color Temperature is the main “color” of the light based on the temperature of a black body radiator. It is measured in degrees Kelvin (Which is “zero” equals absolute zero and the same per degree increase as Centigrade.) A lower Color Temperature, say around 3700-3500K is considered “warm” light and a hotter one such as 7000K is considered “cool” because it is bluer. Yes, it is backwards from what you would think. There is a lot of debate going on about Color Rendering Index as it is more subjective than people realize. It also depends on Color Temperature, so a CRI of 90 at 3700K will look different than a CRI of 90 at 6700K. Why is this important and why do I care??? Well, when it was just incandescent lighting vs. fluorescent you kinda knew what you were getting into.
For me to achieve success with my kitchen counter lighting project I needed one key thing: wife approval factor. As much as I liked LED's my wife has a different opinion. I first had to prototype a 4 foot section and do a side by side comparison. The LED's won!
There are a lot of power LED's available these days from Nichia, Cree, and Seoul Semiconductor. All are available in warm or cool Color Temperatures. The LED's I used, I lucked into. I got a bunch of 1 watt Nichia emitters that have a color temp of 4400K and a high CRI. Unfortunately for me, they were bare emitters, not mounted on a star PC board.
Another piece of the puzzle I needed to figure out was: How much light do I need? Light gets measured in “Lux” which relates to “Lumens” by means of one lux = one lumen per square meter. Check here for more info: Interestingly, there is a push to have light bulbs listed in lumens instead of watts as that measurement is more relevant to what you see. There are also recommended levels for the amount of light that should be present in living and working spaces. Check that out here OK, with all this background info I was ready to start...