Color temp and white balance

I'm not sure this is imaging issue but seems that this forum is closest. Here's my query. I'm somewhat familiar with the Kelvin temp scale and adjusting white balance in my RAW editor. But here's what I find confusing. The temps in Kelvin have the warmer reds/oranges/yellows in the lower end of the scale (2000-3000K) and the cooler blues around 6000K or so. Now when I open an image in RAW and it looks too cool and would benefit from being warmed a bit, I do that by adding 200-400 degrees to it. Like going from 4800K to 5200K. That seems counter intuitive to me. But it works. Can someone explain to me why this is so?

Peter - The reason is that the Kelvin scale for white balance comes from the light that would be emitted from a "blackbody" based on its temperature. (A "blackbody" is a theoretical object that absorbs all light falling on it, and can emit light dependent on its temperature.) Higher temperatures would emit higher energy light, which means a shorter wavelengths, which means "bluer" light. Likewise, lower temperatures would cause longer wavelengths to be emitted, leading to "redder" light.

So when you adjust your white balance, you're really trying to match the "temperature" of the light the scene was shot in, in order to produce something neutral. Since the bluest light is at the highest temperature, moving the slider to a higher temperature removes the blue in order to make the image more neutral. Likewise, if you have a shot made in a low temp light, like 2500-3000, moving the slider to that value adjusts for the red light to make things more neutral.

Now here is where things can get particularly confusing. We often refer to adding red/yellow/orange as "warming an image up", and as you move the slider to higher temps, you get an image that appears to be in redder light. You're actually moving the slider to the bluer end, indicating that you want to remove more blue; And you're moving away from the color temperature that's actually the red/oranges/yellows. The reverse is true for "cooling" an image. You can think of the slider as choosing what light temps you are removing.

Now depending on your RAW program, they could choose to show the colors associated with the temperatures based on the blackbody radiation (i.e. blue on the highest temperature end, and red on the lowest), OR they could choose to show the colors the way they appear to affect the image (i.e. red on highest temps and blue on the lowest). ACR in PS and Lightroom I believe show it the second way, with blue on the lower temps, and red on the higher temps.

In laymen's terms if you look at a flame the hottest part would be the blue/white area of the flame, as the flame losses heat it goes more towards the oranges and reds . The white balance is trying to balance the light to the Kalvin scale , blue being hot , red being cooler. We as humans associate blue with cold and red with warm , the Kalvin scale doesn't care what we mare mortals think !!