Color Balance And Color Temperature
by William Lulow
Way back in the days of film, there were really two basic types of color film: Daylight and Tungsten. One was balanced chemically to be used outdoors or with electronic flash, and the other, for use indoors with ordinary lightbulbs or with photofloods. You could change one to the other by the use of special filters, if you didn’t have both, but that was about it. Then there was always fluorescent light and mercury vapor lights (used in large arenas) which could wreak havoc with color balance. (Since fluorescent light tended to be on the green side of the color spectrum, we would always wrap them with magenta filters when shooting indoors with strobes). Without getting too much into the science of color temperature, suffice it to say that it is measured in “degrees Kelvin.” This “standard” was named after Lord Kelvin (William Thomson), a British mathematician who lived from 1824 to 1907. He believed in being able to measure things. The Kelvin scale measures the relative coolness or warmth of various light sources. For instance, a match flame registers about 1,700 degrees Kelvin or 1700K. An ordinary table light bulb registers approximately 3200K, a fluorescent light about 3000K and daylight, about 5,500K. The higher the degrees Kelvin, the cooler or bluer the light. The lower the number, the warmer or yellower the light.
Today, our DSLRs are capable of all sorts of settings that alter the color balance of images we make, so, it becomes necessary that we study color balance and determine for ourselves what we want our settings to be. Even so, we probably would want skin tones to look “natural” and all other objects to retain their “normal” appearance. Most digital cameras have a setting on one menu that is called “Picture Style” or something similar. There are quite a few presets under this menu. On my Canon DSLR, these are:
- (3) User Defined settings
Within each of these presets, you can further define them as to:
- Color tone
So, right here alone, you have about a dozen ways you can alter the appearance of any image captured by that Camera.
Whoever said that digital photography was easier than shooting with film must have been crazy! How do you figure out what is “normal” color balance or temperature?
One of the ways to determine this is to do some experimentation. Try the presets as they are set by the camera manufacturer as a starting point. Make careful notes as to what they are and then make some images of the same subject – a person would be best. My suggestion would be to make a series of 4×6 prints so that you can line them up one by one to see the difference. I realize that this introduces some more variables such as paper, printer, inks, etc., but for now, it’s a good place to start.
From there, you would need to make changes in the settings as you got closer to your “ideal” colors. It is beyond the scope of this particular article to present all the variables here, but this would be the procedure. Here are a couple of examples of what I’m talking about:
The image on the left was shot with the “STANDARD” setting and the other with the “PORTRAIT’ setting. Note that the second is a bit “warmer” in skin tone that tends to be more pleasing to the eye. The differences may be subtle, but are nevertheless important.
Ordinary daylight on a cloudless day registers about the same color temperature as that emitted by an electronic flash unit. This image was made on tungsten film but cross-processed in a developer made for daylight images, hence the bluish cast:
Today’s DSLRs are capable of setting a “White Balance” for each exposure that automatically measures the degrees Kelvin of a scene and adjusts the color balance accordingly. There could be times when you might want to set the white balance manually. You have the ability to do that by adjusting the color temperature dial in the camera. If you are shooting at sunset for instance, and you want an interior to have a “warm” feel to it, you would set the white balance to 3200K. This would register the lights of a house normally, while giving the outdoors a bluish cast. This makes for an “inviting” looking image due to the warmth of the interior light. Here is an example:
The use of the white balance control in your DSLR can be a source of interesting images, but you must experiment with it (as with most photographic tools) until you learn how and when to use its features.