Using (misusing?) RawTherapee's CIECAM02 to capture the color of the light
The color of the light
When interpolating a camera raw file, an important decision is what white balance to use, the answer to which depends on the photographer's goal for the image. Two common goals are:
- Correcting the color of the light to make it look "as if" the image were captured under Daylight lighting. This is commonly done using a white balancing aid such as a neutral white object placed in the scene.
- Capturing the color of the light, such as capturing the golden glow of a scene illuminated by candlelight, or the much colder light of a rainy day. Capturing the color of the light is often done by using Daylight white balance.
Using CIECAM02 to set the color of the light
When the light source is a tungsten bulb, in my opinion using Daylight white balance to capture the color of the light produces an image that is too orange and too saturated. So I experimented with using RawTherapee's CIECAM02 module to chromatically adapt an image with an already corrected "color of the light" back to something approximating the color of the light that illuminated the original scene.
I set up a studio shot of a lamp with a tungsten bulb, for which the only light source was the light from the tungsten bulb. The slideshow below compares using Daylight white balance to using CIECAM02 chromatic adaptation as ways to capture (or modify, as per slide 5) the color of the light coming from the tungsten bulb:
Based on comparing the "real life" lamp and the lamp on my computer screen, I think slides 3 and 4 are both very convincing renditions of the actual color of the tungsten light coming from the bulb. My husband says slide 4 (slightly more orange), is closest to reality and I think he's right. But I think slide 3 (more yellow) is prettier. Both of us agree that slide 2 (using Daylight white balance) produces overly orange and saturated results. What do you think?