by bdosborn » Mon Sep 16, 2013 4:55 pm
JuneBug wrote:Bogo wrote:jstrubberg wrote:BrwBier wrote:Wolffarmer wrote:Actually it all depends on the LED. A monochrome green or red won't, but a white one may. Most white LEDs are really a UV LED shining on a phosphor that then changes the UV light into visible light. Some of that UV light gets past the phosphor. There are also LEDs that just emit UV light.
Would you translate this into what would make a nice (relatively warm) reading light? Some LED lights just don't seem like they are conducive to a positive reading experience and would cause eye strain.
Look for a color temperature of 2700K for mostly yellow colored light. 3500k will be white with a slight blue tinge. Anything above 3500k will be noticeably blue. Everyone has a different perception of LED light colors so YMMV. The inevitable gotcha is that while most people prefer the lower temperature colors, the higher temperatures are more efficient. Another measure you can look for is color rendition index (CRI). The higher the number, the better and more realistic colors look. Sunlight is 100. I look for a number higher than 80 but it can be hard to find the CRI. Most of the Chinese manufacturers don't publish it ( for obvious reasons).
Bruce
Bruce