Today’s Question: Can you address Auto White Balance (AWB) versus choosing Cloudy or Sunny or a given Kelvin temperature? AWB tends toward a blue cast. Is that fixed in the RAW file and can that be removed by changing temperature in Lightroom?
Tim’s Quick Answer: If you are shooting in RAW mode, the white balance settings you establish in the camera are purely metadata settings that establish the default adjustments when processing the RAW capture. Therefore, setting an optimal white balance compensation in-camera provides only a workflow benefit, not an image quality benefit. For JPEG captures, of course, the settings are fixed in the image, making those white balance settings important for JPEG capture.
More Detail: Current digital cameras generally do a very good job of determining a good setting for the white balance compensation, resulting in relatively accurate color in your initial captures. That is especially true under “normal” conditions, such as daylight. However, as noted in the question today, those settings are not always optimal. Fortunately, for RAW capture you have complete flexibility to refine your settings when processing the images after the capture, with no penalty in terms of image quality.
For RAW capture the white balance settings (generally a color temperature and tint setting) are simply metadata values. Those values will become the default settings for the RAW processing in Lightroom, Adobe Camera Raw, or other software. But you can refine those settings as needed to get the best final result, without any negative impact on the image quality.
In other words, from the standpoint of image quality, it doesn’t matter at all which setting you’ve used for white balance in the camera if you are shooting in RAW mode. No matter how inaccurate the settings are, you can adjust in post-processing.
Of course, from a workflow standpoint it is generally advantageous to have the color as accurate as possible in the initial capture. Thus, you may want to choose a specific white balance preset (such as Daylight or Cloudy). You can also dial in a specific Kelvin value to shift the balance between blue and yellow. For most cameras you’ll also find a Tint control, allowing you to make adjustments on a green/magenta axis. You can even use a “custom” option in many cases, where you photograph a gray card or other neutral target and use that image as the basis of an automatic in-camera white balance adjustment.
You might even find that setting the “wrong” white balance preset provides you with a good starting point. Using the “Cloudy” or “Shade” setting even on a sunny day, for example, will result in a photo that is a little warmer (more yellow) than you would otherwise achieve. Again, this isn’t critical for RAW captures, but may provide you with a workflow advantage, and a more pleasing image to review on your camera’s LCD display.