Let’s talk about the color of light. Although you may hear the expression that light is light. That applies to the behavior of falloff and wrapping etc. It does not apply to the concept of color. Even sunlight is not always the same color.
Now, we will have to go a little bit on the technical side for this article. Light is measured in degrees Kelvin. The “Cooler” the temperature of the light, the more the light is a blue color. The “Warmer” the temperature of the light, the color will be more towards orange.
Bright daylight is normally around 5600 degrees Kelvin. Incandescent bulbs term to have a warmer color. Fluorescent lighting tends to be a little on the cooler side. Additionally, other type of lighting add their own color cast. These are important to keep in mind as sometimes in rooms you can have multiple types of lights which can add multiple types of color cast into your image.
For a very simple example. The image below was shot using natural light and also has an incandescent light to the left of the model.
You can see a difference in the color of the light on the left side compared to the right side.
In some cases it’s not a problem that the colors are different. But sometimes it can wreak havoc on your image. This is where using white balance can be a huge. There are several different options out there. The simplest is buying a “Grey card” which these days is usually a small collapsible square or oval “target” that has one side colored at 18% grey. Take a picture of it in the lighting. Then during post processing, you can click on it with the white balance dropper and suddenly your image color has come back to what you would expect it to be.
Sometimes you want that color from the light in the image. For example if you are shooting a candlelight service/vigil you want that warm orange glow from the candles.
Believe it or not, I rarely ever use automatic white balance. When you use automatic it guesses every time. The white balance per image can be different on every shot. Additionally, if you want the color from the lights, say that orange glow from the candles, auto-white balance can correct it out. True story, I was shooting a candlelight service on Christmas Eve and I had on auto white balance and it took the orange glow out. Every picture was going to have to be corrected to put the glow back in. I was furious.
Now, believe it or night, natural light is not always the same color. Even if there is no window treatment, a northern facing window will have a different color light coming in than a southern facing window. In Phoenix, the Sun tends to be in the south. Light coming in through a northern facing window will actually have a cooler temperature than light coming in from a southern window. Often enough you should adjust your white balance to correct it.
Other times are during golden hour, blue hour, or even during overcast days. In each case, sunlight will have a slightly different temperature.
The other side to consider is the colors around you when you are shooting. Especially when using strobe. You see when you see an item that is green. What you are seeing is the color green reflecting off the item. The reason I bring this up is if you have light bouncing off a colored surface, the color of the light can change and bring in a hue of that color.
For example. If the room has a red wall and you bounce light off it, you can get a slight red hue in your image. Again, this can be desired, or easily corrected using white balance.
The most important is to be thinking about the light that will show up in your image and how does the color of that light affect your image. Then you can correct or use those colors depending on your vision.
Hopefully this has you thinking about light color a little more. Keep shooting/creating!
Scotty Myers http://www.scottymyers.com/