Understanding color temperature

 

Do your pictures sometime look like these? Really Blue or really orange/red? Well then you are having a color balance issue.

In last week’s post, I talked about shooting at night with Tungsten lights. The white balance that you shoot on is determined by the color temperature of your light source. Like many things in photography there is no right or wrong way to shoot. It is all relevant to what you want your end result to look like. Generally, I am looking for a neutral white balance in my food images, so this tutorial is written with the goal of having a neutral White Balance as the end result. By neutral I mean that white looks white. There is no warm or cool cast to it.

 

You can get great neutral looking pictures with each source, but you can not shoot them on the same white balance setting. The Fried Cookie Dough was shot using daylight or a light source of 5200K and the Daylight White Balance setting.  The Doughnut French Toast was shot with the tota and a light source of 3200K and the Tungsten White Balance Setting. What are 5200 and 3200K you ask? Those are the Kelvin Temperatures of the light! If you have never heard of the Kelvin scale then let me explain.

Basically the scale goes from 0 to 10,000. It measures the “warmness” of a light source. Every light source has its own temperature. The closer a light source’s temperature is to 0 the oranger the light will look. Closer to 10,000 will give a bluer cast (this is a very simplified version of what the scale is, you can google Kelvin Scale to learn more about the physics behind it if you wish).

The two most common light sources you will run into are Daylight and Tungsten light.

Light when it is high noon and clear outside is around 5,000-5,500 degrees K (different sources will tell you different readings so I am going to average it to 5200K). Your flashes are calibrated to try and be at this temperature. They are by no means perfect, flashes will change color temperature through out the bulb’s life and even while using. One of the reasons why studio strobes can be incredibly expensive is that they will produce a consistent color temperature throughout their use and not change when using.

Tungsten lighting is around 3,200 degress K. This is the lighting you see frequently in your home or restaurants, it has an orange looking glow to it.

When shooting outside or in mixed lighting environments there are dozens of other factors that will effect the color temperature and there are entire books written just on color management, so I am going to keep this simple and just talk about using the white balance modes on your camera to help your images. If you want truely correct color, then you will need to color balance using a custom white balance, use an expo disc or Whi bal card, and do some color correcting in post processing, that is another post. That being said, just consider this an introduction into color temperature.

So, how do you control for these different lighting conditions ? You do this by changing the white balance mode in your camera. Every camera is different, so consult your manual on how to do this and what the different symbols mean. A mistake some people make is using a white balance setting inappropriate for the lighting condition that they are in. I shot this at night using a daylight balanced flash and a tungsten light.

There are settings in cameras for shade and overcast White Balance. This will produce slightly warmer results than daylight, I am not going to cover them here, but you are free to play around with those settings as well.

These lights have completely different temperatures, but by using the appropriate White Balance Mode, I can achieve a close to Neutral White Balance. In the Tungsten picture, I shot using the Tungsten White Balance setting in my camera. My camera’s manual says this is approx. 3200K. For the Strobe Shot I using  the daylight White Balance  setting which is approx. 5200K.

Here is what happens when you shoot with Tungsten light( Temperature of 3200K) in the Auto WB mode, Daylight and Tungsten White Balance modes.

Notice how the Tungsten Balances setting is the most neutral with Tungsten lights.

 

Here is the same scene under a strobe with color temperature of 5200K.

 

 

Notice how the Daylight Balanced setting is the most neutral with the strobe. Color temperature preference, again is something that is subjective, but now you know that you can change the look of your photos under different light source temperatures by changing the White Balance setting in your camera.

With every light source having its own color temperature, make sure that you are on the correct mode when shooting. If you are outside then it is going to be Daylight, Overcast, or Shade setting. If inside under a tungsten lamp, it will be tungsten setting. If inside with flash it will be daylight. Play around with the different modes to find what works best for your situation! When you change lighting environments don’t forget to change you White Balance mode!

If you have any more questions or other topics on food photography you would like to see then let me know and I will try to answer them.