How many of you remember your physics class? I certainly don’t. Color temperature and white balance can be a bit of a challenge—especially when shooting underwater—so let’s take a look at exactly what they are.
A term borrowed from physics, color temperature has everything to do with heat. It is a characteristic of visible light that has important applications in lighting for photography and videography. For those of you who love to read all the detailed technical aspects of color temperature, you can easily find it on Wikipedia.
Take a look at the lighting in your own home. You’ll see different color casts of lighting. For example, a fluorescent light has a blue to green color cast while tungsten lighting produces a warm yellow-orange tone. What about the sunlight outdoors? Morning light is soft and golden while noon produces a different cast altogether.
To put it in further perspective, here is a quick look at approximate color temperatures for a variety of lighting sources:
||Candles; oil lamps
||Very early sunrise; low effect tungsten lamps
||Household light bulbs
||Studio lights, photo floods
||Subtronic, Seacam Strobes
||Typical daylight; electronic flash
||SEA & SEA Strobes
||The sun at noon, INON strobes
||Bright sunshine with clear sky
||Slightly overcast sky
||Open shade on clear day
||Heavily overcast sky
||Sunless blue skies
||Open shade on a clear day
I know, you probably thought that higher numbers would be warmer. Actually, 5000K or more are considered “cool” temperatures which produces the green-blue and lower temperatures are considered “warm” producing more yellow/red. It follows the colors of the rainbow, ROYGBIV.
I find color temperature in a final image to be a very subjective thing. For any of us old dogs who shot film, it was a matter of personal taste whether we chose a film like Fuji Velvia, which was very warm thereby producing vibrant reds ,versus a Kodachrome, which some felt was more “normal.” However, what is normal is in the eye of the beholder. With digital, we can do so much more. We can make choices in our color temperature when we capture the image, by the strobes we choose or by the adjustments we make in post-processing.
Example of how you cannot always use the eyedropper in post-production. See how the water behind the ray has a purple/magenta hue?
Here is how the photo looks with proper Photoshop post-production.
It’s impossible to talk about color temperature without talking about white balance. The white balance is a function in your camera used to adjust how warm or cool your image will appear. You may want to go back and review the Ambient Light lesson here on Adorama Learning Center we posted in September. It’s a reminder that we have no warm color below 10 feet in underwater photography.
I highly recommend that you shoot in RAW format. There are significant differences between JPEG and RAW files, and the JPEG already has had some white balance and other adjustments automatically applied by your camera. It is a total fallacy that you cannot adjust white balance on a JPEG. You can adjust the color balance of any file type. However, I like total control and using RAW format gives me much more to work with since JPEG loses a lot of the color information.
Most cameras, including point and shoots, have a way to set the white balance. If shooting in ambient light, you are definitely going to use a custom white balance. Most compact systems without a custom WB function have presets. In any case, you can make a choice from the symbols appearing in the camera menu which may include cloudy, flash, fluorescent, tungsten and daylight. There are a few compact cameras that have an underwater mode, but I recommend doing a comparison test to see what you think looks best. Although auto is not necessary recommended, try auto, underwater and shade modes to compare the differences.
The most accurate way is to manually set the white balance. This will require you having a neutral object, such as a white dive slate, to measure off of. You will have to reset this every 10 feet in depth or so, to be accurate. If you are using flash, you will need to make sure you camera is set appropriately or you will have very red looking images.
First of three images: The first image is “as shot” from the camera. Your strobes can only light a small area of the image.
Watch where you select for white balance or it can produce extremely distorted colors. I used the color picker off the white fins in the background and the small white area on the wreck wheel.
This photo utilized more definitive manual color balance adjustments done in Lightroom. See how much more natural it looks, especially in the skin tone of the diver?
White Balance in Post-Processing
I am a huge proponent of Adobe Lightroom. It is one of the most powerful tools for not only archiving but making adjustments to images. The good part is that it does not change your RAW file. It adds what they call a sidecar file or EXIF file where the changes are made. There are several other programs available, and you can also use Photoshop to make white balance adjustments—but Lightroom is so easy!
The tool is basically the same for most programs. There is a symbol in the develop mode—usually an eyedropper—that can be used to select a neutral-colored part of the image. You may have to test a couple of areas, but the results can be viewed immediately. The sliders for temperature and tint can be used to fine-tune the image. It is important to not get carried away with the adjustments or the images can look like something from a psychedelic poster.
You cannot light a large area with your strobes. This shot is without WB adjustments.
WB can be corrected in the camera or in post-production. The soft muted colors of the coral now make for a pleasing shot.
Another example of “as shot” in camera with no custom WB setting.
Final image using manual adjustment in Lightroom.