Photo Technical

Options to correct the color of photos in different lighting – A60

Welcome aboard photo enthusiasts. I’ve received some follow-up questions relating to recent articles on underwater photography, specifically how to handle color correcting with software.

How best should that be done? Is the idea to make it look like it isn’t even underwater, or do you save that blue-heavy hue?”

Let’s explore why we even have the color-shift problem that requires correcting.

What is the color of light? It depends. Are we talking daylight, blue-sky light, cloudy-day light, candlelight, tungsten light, or fluorescent light?

All light has a degree given as Kelvin. Candles are rated at 1900IC a 60W household bulb at 2800K, a tungsten light 3400K, a sunny clear sky at 6000K. Your pocket camera flash is rated at 5800K.

The latter two are the most natural compared with our human vision, while the first three samples given are warm, leaning heavy to the red spectrum of light. Anyone having photographed a bathroom with tungsten light will find the results having a warm yellow tone. Photography underwater will tend to shift more heavily to the blue end of the spectrum. Why? Water blocks the red spectrum of light from entering, so photographs can look excessively blue.

Cameras have a limited capability to deal with these color shifts when compared with our vision that will adjust to some extent; or at least the color shift will not be as glaring to our eyes as it can be seen in a photograph. How can we prepare our photographs to simulate what we naturally see with our eyes?

We can control the light; manually set the white balance in our camera; use the auto white balance setting, or make a color correction adjustment using computer software.

The first option, for controlling the light, can be difficult. There’s no changing the sun, but midday sunlight is well balanced for color so that’s never a problem, and most light is what it is.

There are exceptions. For Instance, fluorescent light can be balanced for a warmer Kelvin rating or it can be obtained to give nearly a full spectrum color rendering index output to simulate daylight. By the way, full spectrum fluorescent is a wonderful, soft shadow source of lighting.

Another way to control the light, even in situations where other types of light are in use, is to add in your electronic flash, with the output close to daylight. The flash output on our pocket cameras lacks serious power; nevertheless it may balance existing light to some degree.

The second option, manually setting the camera white balance, is a way of adjusting color output, matching the existing light used to more closely match normal daylight. In other words, that tungsten-lighted bathroom where the white walls would normally photograph as yellow will come out as they should look… white.

To make this adjustment, set your camera’s menu to make this white balance adjustment. Place a white piece of paper under the lighting you will be using. Point your camera at the paper making sure it fills the frame, and press the white balance setting. Now, your camera should be properly set for photographs under the type of lighting you are using (tungsten, candlelight, etc.). This option will not be handy for underwater photography. If you change the lighting, you have to reset the white balance adjustment.

If you use the third option, the camera will automatically white balance. Often, lighting can be from light sources such as daylight and tungsten lighting mix and an auto setting may do a better job of figuring out that conflict. I find that bathrooms using tungsten lighting still come out looking yellow with auto white balance, nevertheless, it is a good option in general and I use it all the time.

If I need to make adjustments in the white balance of my photographs, I rely on software, which in my case, is in Adobe Photoshop Lightroom, but there are many programs that can make the adjustment. For instance, the free program Picasa can make them easily.

Should the color correction of a photo taken underwater be made to look like it wasn’t taken underwater or should you keep that blue-heavy hue?

Unless I was looking to create something surreal, I always make my corrections as realistic as possible, which would be how I remembered seeing it. Using auto white balance, the overall hue could be too cold and blue, so I would add some warmth.

How can you make that determination? Possibly the underwater shot you’ve taken has sand (or some other color identifier). If the sand has a blue hue, correct it to look as you know it should, a light tan color. While you’re doing that I’ll take my leave to go ashore.

James Schot has been a professional photographer for more than 35 years and has a studio/gallery in Ft. Lauderdale. Send questions to james@ bestschot.com.