White Balance Bracketing
Learn to control the white balance by bracketing
White Balance bracketing is a function on your camera that compensates for different colours of light being emitted by different light sources. When a camera has been calibrated to correctly display white, the camera is white balanced. Once it is calibrated for white, other colours should display true.
It is a way of calibrating a camera’s colour response to take into account different colour temperatures of light. For example:
This calibration allows the camera to define what the colour white is under any of these various lighting conditions. Failure to white balance your camera could result in an unsightly, unnatural colour cast.
With digital SLR’s for example, you will normally find a yellow or red colour cast when using "Auto White Balance" in JPEG mode. Particularly with Canon cameras shooting indoors.
This is no biggie and is easily corrected in Photoshop using the colour correction tools as explained here. There are three main ways to get the correct setting for white balance;
White Balance Bracketing
Use a grey card to take a reading from the scene in which you are photographing.
A custom, or preset, WB setting requires a grey or white card to allow the camera to lock in a particular colour temperature based on what it sees from the reference card. You set the camera to its custom WB mode and with whichever lens you’re using, fill the frame with the grey or white card and take an exposure.
The camera takes a second to process the information. It will then indicate whether the custom WB is good or not. Obviously you want to ensure that you hold the grey card in such a way so that the ambient light falls on it in order to take a custom WB reading.
Once the custom WB is set, you revert back to shooting mode. All exposures taken will now reflect this colour balance until you adjust the WB setting again. The grey card method is relatively cheap since grey cards sell for $20 or less. This is a favoured method for JPEG shooters because it helps to reduce post-production editing significantly. It also allows for a fairly neutral colour balance (depending on the age and condition of the grey card).
White Balance Bracketing - Shoot RAW
By shooting RAW, you are able to adjust the white balance after you have taken the shot, during post processing. When your file is opened, you can adjust the white balance or colour temperature to whatever setting looks correct.
This for me is the best way of making minor adjustments to a shot when I don’t have time to mess around during the actual shoot. It is also why I always shoot weddings in RAW mode.
White Balance Bracketing - Bracketing
Maybe you are fairly confident that the white balance setting you are using is close to being right. If indeed you are using "Auto White Balance", you can almost guarantee the correct setting by bracketing the shots.
As with exposure bracketing, you can take 3 shots with differing WB settings. Shot one will be as you or the camera set it. Shot 2 will be higher or "warmer" and the last one will be lower or "cooler".
You can vary the increments according to your cameras allowances (i.e. 1/3rd, ½ stops). I would recommend that if your camera has this feature, have a play and practice in different situations, i.e.