Tuesday, October 18, 2011

Color Balance

Welcome back, Volks! Today we're bringing the subject of white balance to Hohenfels Volks.

Generally, white balance is an adjustment made to an image to make your neutral colors, neutral. What we really mean when we speak of white balance is color balance. Color balance removes colorcasts, or imbalances, caused by shooting in light of differing temperatures. Color temperature theory is a little too much for me to explain, so simply put; blue light has a high temperature in degrees Kelvin, as it requires more heat to create. Red requires less, so it has a lower temperature. Who knew engineers would create such a complex way of thinking about colors?

The sensor in your digital camera measures the temperature of the overall light to create a general color balance when set to automatic. It then adds or removes colors that remove the colorcast. In single lighting conditions, automatic can do a good job for you.

The difficulty comes in when we realize that we really don’t shoot with one color light. If you’re shooting on a nice sunny day, there is still light that is differently colored than the sunlight. This is caused by the nature of light. Light has no respect for your boundaries, and doesn’t stop only on your subject. Light tends to reflect and bounce everywhere. So, on this bright day, you’ll have light from the sun, light bounced off buildings, trees, grass, windows, and many other sources. Yikes, time for “white balance.”

When you use a preset white balance, you are telling the camera what type of light you used. The camera then adjusts for that type of light. For tungsten, it removes yellow and/or adds blue. For fluorescent, it adds green and/or removes red. You may end up with a bad colorcast if you have multiple color temperatures that vary by too much.

Shooting in RAW mode allows the most control, so what I describe will work best on images shot in RAW format. There are several options to deal with color temperature in RAW images. The first is to use a preset, as mentioned above. The second is to adjust your color temperature manually. The third is to click a neutral color. This last one can do a good job if you have a large enough neutral area. It samples a variety of pixels around your selection and applies the adjustment to the entire image. There are 2 more that I will mention here. The first is to use an Expodisc, or something similar. This fits onto the end of your lens, and then you take a photo of either your light source or your subject, and apply the resulting image as a custom white balance to your camera. The other and probably better way, at least for most, is a white card. You can use plain white paper, but it tends to have variations in the tone and colors, even between sheets. Your best bet is to get a white balance card. They are made to ensure your neutrals stay neutral. When using a custom white balance, if the lighting changes, you must do a new custom balance source to ensure accuracy.

For best results, take your white balance card and place it with, or near, your subject. Ensure the lighting is the same you will use for your subject, and fill your frame with the card. Make sure there are no colors in the frame, and click your shot. Then go into your menu and select custom white balance. You will have to choose the image you just created, and then apply it. All your shots taken in that lighting will be properly color balanced.

You can also batch color balance in your RAW conversion software by selecting your white card shot and selecting the source, then applying it to all your shots taken in that lighting.

The order of white balance settings in this sample chart is from left to right; as shot, Daylight, Flash, Shade, Cloudy, Color temp 5800k, Click on white, Tungsten, Fluorescent, with the last square white for reference.

There is a lot more to color balance, but this should get you going. Just remember that getting it right takes some practice and knowing your camera.

Thanks to Jennifer O for the suggestion for today's topic. I hope to hear more suggestions and comments! Your input will make this thing of ours great!

Here’s hoping the rest of your week is filled with loads of photos of Hohenfels, and lots of joy! Don't forget to share your pics and questions by posting at the Hohenfels Volks Facebook page, or commenting here!

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