I have been writing on color temperature before, but in the perspective of White Balance. I have noticed that a great deal of photographers are satisfied with Auto White Balance, causing them to spend a great deal time and investing effort in the develop module in light room. This blog post is going to dive into topic Color Temperature, and it might get somewhat detailed. I am going to argue that understanding color shifts is a keystone in photography. For now, I am going to assume that you have corrected the color gamut of your computer display; if not… you had better to get at it.
I shoot Raw for many reasons, but I should I choose one reason alone to use raw then it would be the ability to change color temperature. By shooting in your pictures in RAW format, you have much more information to play with. You have all the information that every pixel recorded at the time of the exposure rather than the cut down ‘subset’ of information that is saved after the camera has compressed your picture into jpeg format.
When shooting in Raw, should I care a rats arse about Color Temperature
The short answer is, depends, seen from a technical perspective no, there is no reason why you should bother; everything can be fixed in post-production. You need to be able to spot the potential of the colors in a scene and then use them in your images. The choice of Composition, choosing the color contrast starts before you even pick up the camera. How you see the colors and how they influence our perception of the world is the key to producing great color photographs. Color contrast is the way colors in your photography enhance each other. Complimentary colors are opposite of each other on the color wheel accentuate each other, you can read more on this in my blog post Contrast is for your eye and mind.
How we see color
Our eyesight and mind is good at comparing two colored objects and judging if they match. However, there is conditions; for us being able to judge the objects, they have to be judged together and under identical illumination. We are not very reliable when it comes to color seen in isolation. Judgement here varies from person to person and from one set of circumstances to another. Colors become personalized and you cannot even trust your own eyes.
Eyesight inconsistencies maybe a bigger factor than you think, around 10% of the male population and 0.5% of women have some form of defective color vision. Their trichromatic response may simply be uneven or, more severely, they cannot distinguish between red and green. In some cases, which are rarer, there is defective color vision for yellow and blue hues. Add age to the factor, the optics of your eyes grow yellower with age and it seems that we must all see color differently.
It is not only eyesight inconsistencies that is a factor when getting the colors right. Perhaps the most important factor is our brain, it is so darn great at fooling itself. If you look at white surface, it will oddly appear white in most lighting conditions. This is because our brains is playing a trick on us. If you look at a white object in various lighting conditions then the white should change. Only our brains fools us to believe that what we see under an incandescent tungsten lamp may be the same as we see in pure sunlight, but I can assure you it is not. The reason is that the human brain compensates for these differences in color temperature automatically. This is true in most cases, yet there is situations where our brain will not compensate. One of these situations is when both types of light is present in the same scene.
Experience and memory also plays a major factor in our judgement of color. The photographer might swear that the color of the grass in his photography, is of the same color at it appeared on the field, but is that a fact, or just another subjective perception. It is a proven fact that we remember colors more saturated than the colors in the original scene and our remembrance of luminosity is at fault as well. Perhaps the worst trap is familiarity, recognizing an object may your unconsciously accept its color even if it is clearly distorted.
As I started out with, is our brain great at judging colors, when these are not seen in isolation, if you consider the info above you might see the logic in introducing a reference scale. I have seen many different kinds and for all wallets, but often it is sufficient having a true black, white and 18% grey.
Color temperatures measured kelvin and practical start when moving away from AWB
We measure Color temperature in kelvin. When we talk about photos then color temperatures it is usually done in greatly simplified terms, we referrer yellow and reddish tones as warm tones, whereas we call blue and black cold. Daylight has a color temperature of between 5000K and 6000K. Thus, midday sun is generally set to 5500K when shooting under the midday sun then it is not always so; remember the temperature of daylight varies at different times of the day and because of different weather conditions.
When you move from AWB then it is worth looking into the typical kelvin ranges vs weather conditions, you can find more info about this in my blog article on White Balance here you will find an in-depth schema of varying kelvin vs types of light. Remembering the schema in detail might be unpractical, especially if you come unprepared.
Carrying a reference color board around is often not that practical, nor is that common that people own a color reader. What I do is caring around a microfiber cloth to clean my lenses and camera, which happens to be 18% grey; this is great hack to color balance my A99. Yet it is not always possible, at many times I just judge the color temperature of a scene. If you find it too difficult to remember a schema or find it troublesome to judge the ambient light, then you might find comfort in the preset white balances.