White Balance – Something to Consider
In a recent trip to the coastal redwoods in California I was reminded of something that all digital photographers should watch for – Auto White Balance errors by your camera. I (as I am sure most people) tend to rely pretty heavily on my cameras ability to auto white balance. Since I shoot RAW, this is not as big of a commitment as it would be if I was shooting JPEG (more below), but it still can get me in trouble at times.
California Redwoods - White Balance Example - Photo on the Left is Auto White Balance the photo on the Right is Shade preset.
First – a short Description of what we are talking about. The light that illuminates any scene has a color to it, or a color temperature. Our eyes and brain, being amazing instruments, filter this color out so we see whites as white, blues as blue, greens and green, etc. in almost any situation. The fact that sun light is very blue and incandescent lights are reddish and florescent bulbs are greenish, generally do not mess up the ability of our eyes and brain to see the right colors – Unfortunately our cameras often have a much harder time at this. So generally we have three options on our camera – Setting Auto White Balance, setting one of the presets (often Sun, shade, clouds, incandescent, florescent, flash and manual), or the final option where some cameras can read the white balance from an image that you have taken of a white or neutral object under the light you are shooting in. There is a fourth option, which is to figure it out in post processing, which I generally rely on, but it is good to give yourself some help by get it at least close in the camera.
As I said at the start, most of us use the auto white balance of our camera and hopefully you are shooting RAW. Different cameras have a varying degree of accuracy when using auto white balance, but even the best cameras can blow it at times. Furthermore the camera presets are just approximations and often need fine tuning. The Auto White Balance feature in most cameras generally do a good job, but at time the lighting situation can being rather tricking, such as the above mentioned California Coastal Redwoods. In situations where the light is heavily filtered, being reflected from a non-neutral surface, or your subject or frame is mostly one color your camera can have a very hard time determining the correct white balance and at times will choose an incorrect white balance. This will result in images that just do not have punch, saturation or contrast.
To further compound this, when shooting in JPEG mode the white balance that the camera is set to or reads in auto white balance mode is used to process the final JPEG and therefore the camera bakes the white balance into the image (the image data/color will be changed with the white balance data in attempt to correct the image as the camera process the image into a JPEG file), as a result it can be very hard to make corrections to white balance in a JPEG image. In the case of RAW format, the white balance setting (or calculation in the case of auto white balance) is simply written into the header of the file as a color temperature and tint to let the processing program know what the white balance should be (at least according to the camera) – the actual image data is not altered, it is still the image data right from the sensor. It is up to the RAW processing software, like Lightroom, to apply any necessary white balance corrections the user thinks are necessary.
Lightroom White Balance
As a result you may be asking ‘I am shooting RAW, so why do I even care about all this white balance stuff, I will fix it in post?’ The biggest reason is to give yourself a base line to work from. It is much easier and faster to process images that are close to your final goal. Part of what I am trying to achieve is to get images that represent what I saw – I have some faith in my memory, but it is helpful to make the image look at least close as it comes up in Lightroom. It is my experience when I am looking through images that just don’t live up to my memory of the image I took, one of the first things I suspect in white balance. Sometime I will even see it at that time of shooting in the LCD.
One place it is important for me is while reviewing my pictures in Lightroom, I use the image previews created by Lightroom as the images are imported to evaluate my images. These previews are created from the RAW files I shoot, the Lightroom defaults I have selected and the whit balance that the camera was set to, or in the case of auto white balance the white balance it calculated. As I am reviewing these images to determine what is usable (this at time could be hundreds of images) I will be forced to make quick decisions about what I am going to use and what will not be used. Small errors in white balance can make huge differences in how the image appears and if I will choose to accept it or rejected it. What I find is these images that have improper white balances will usually not get a reject, but also will not get chooses with a ‘pick’ flag, leaving the image in limbo. The lack of proper white balance make the image have less punch or impact and as a result I just may not think it has what I need in the case of a quick review, resulting in the image not getting the attention it may deserve.
This can be a hard thing to learn and even harder to come up with a solution for, there are some things that can help improve on this situation. Recognize when you might be in a shooting situation where your camera may not make the best decisions on auto white balance. This is often when you are in shade, when the sun is not up (dawn or dusk), using light that is being reflected from a colored object like a building or you are inside under artificial light. Things that can compound this further is when there are large areas of color near you when you are shooting, such as heavy green tree cover, large painted walls, or just a predominant color in the image. And of course electric lights will always through off your color balance.
Keep an eye on your preview LCD to and make sure the images look right for the shooting situation. This is the first line of defense. Learn to read your LCD on your camera. Yes, I know, people make fun of chimpers, but you should take advantage of the technology and learn how to use it, don’t just look at the image, read what the LCD is telling you. Once you get use to seeing images on the LCD, you will learn to spot when things are not looking right. Saturation will not look right or the image will look muted. These are signs that the white balance is not right.
If while in the field you feel like you might not be getting the proper white balance, take actions to improve it. The simplest first thing might be to try the presets. They will often get you close or at least closer to the desired proper white balance. If you need something more accurate or you are shooting a lot of images under the same conditions, such as event or wedding photography, it pays to get the white balance accurate so you are not post processing hundreds of photos with bad white balance. There are typically 3 approaches depending on your situation and post processing technique. Most cameras will use a sample image as its reference image for its white balance on all future images. This allows you to photograph something that you know is neutral gray or better yet a gray card -make sure you fill the frame with it and it is under the light you will be using. You then use the cameras white balance menu to select that image for white balance (each camera does this different), but generally it is not too hard once you have it figured out. Another option is to use this neutral image in post processing to determine white balance and then Sync it across all the images in the shoot under that lighting. Lightroom makes this very easy. Another method that is popular is to use a tool like an Expodisc to make the neutral image. The Expodisc is a lens filter like device that you put over your lens and shoot toward your light source. The resulting image should be used to set the white balance, either in the camera or post.
An 18% Gray Card can be an important tool to insure your colors are accurate by allow you to set a perfect White Balance
OK, you are going to buy a grey card or Expodisc, but in this shoot you did not have one…. What now. The next best thing to just guessing (which is not a bad option) is to look though your images and find a neutral grey color. You will use this grey with the white balance picker to get your color temperature and tint settings, then as above you will sync them across the other images that were taken under that light source.
The other option – guessing… It is an educated guess. How this works is that you are going to select an image that has good selection of colors, in Lightroom or ACR, you are going to choose the preset that gets you the closest to the way you think your image should look. Then you are going to fiddle around with Color Temperature and Tint to get it right. I found that you generally want to leave tint pretty close to zero in most situations. Some minor alterations may help. But color temperature can be set as low as 4000 in some case and well over 7000 in others. If you are outside that range, it does not mean you are wrong, it can happen.
In night photography you are dealing with so many different colored light sources you often must correct to taste. Left is Auto WB, the Right is corrected in Lightroom.
Also keep in mind that in the creative work flow of photography you may want to alter the white balance to set a mood to your image. White balance is just one of the many creative tools you have at your disposal to say what you want with your image. Cooling an image by setting color temperatures low or warming your image by setting higher color temperatures drastically effect the mood and impression of the image.
It should also be noted that color temperature is still enabled when you put Lightroom into Black and White mode. This is because color temperature affects the color relationships and affects the colors before they are interpreted to determine how they will be converted to black, white and grey by the color mixer. Color Temperature can drastically affect the overall contrast of a Black and White image.
The thing to remember here is that even small errors in whit balance can drastically affect the appearance of your photographs. These errors can result in you assuming your shots are not acceptable and resulting in you rejecting the image or at least not processing it further. Worse it might result in final images that does not reach its full potential. Learn to watch for errors in white balance and learn some methods of correcting for it. I think if you do, you will find that you have more keepers in each shoot.
