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All posts for the month October, 2010


Picture it…(already he’s starting in with the puns?) Yes, Picture it….a lovely day, a good friend and a photograph. Let’s say you and your friend are out at a park and you decide what a lovely setting it would be to take a photo of your friend.

Remembering a tip you read somewhere on the internet about how portraits look better when the sunlight is diffused, you decide to have your friend pose under a big, leafy, shaded tree.

You shoot *click*. One more time just to be sure *click*. Then you look down at your lcd screen to see the gorgeous image you just captured…WHY THE HECK IS IT BLUE???!!!!!

Photo with blue color cast

Well now that you’ve destroyed the peace and quiet in the park, and scared your friend off, let’s examine why the beautiful image you were trying to capture came out with a horrible blue color cast.

It all has to do with something called White Balance. White Balance is a camera setting that allows the camera to adjust or compensate for color differences in the surrounding light of the image you are trying to capture.

“Now wait a minute Scott”…you say. Go ahead say it, I know you’re thinking it. “I just shot this photo on a nice sunny day under a tree, trees are green, sunlight is white, where did this blue color light you speak of come from?”

Well you’re only partially right, trees are definitely green, but sunlight isn’t always white. In fact sunlight is rarely pure white. You can check this for yourself, put on a white shirt and go out in the sun at various times during the day.

You’ll notice that at sunrise your white shirt takes on a pinkish hue. As you approach early morning it turns into a bit of a cream color. At sunset it turns into a nice gold. And if you happen to go under a shaded tree you’ll notice that it does indeed appear to be a bit blue.

Shirt Color at Sunrise, Mid-Day, Sunset

This isn’t only limited to sunlight. Go into various rooms in your house, if you have incandescent lights you’ll notice your white shirt takes on an orange tint. Fluorescent tube lights, those appear kind of green.

So how come we don’t notice these color changes all the time? Well as we’ve said many times before the human eye is the best camera ever invented, and it can compensate for this differences in the color of light very well.

Think about it, a lot of us work in offices with overhead fluorescent lighting, but do you spend your whole day at working saying “gee, everyone looks so green in here today”? Of course not, because our eyes and brains compensate for the color shift.

Our cameras are not so lucky they record the color of light exactly as it appears. So when you took that photo of your friend under that shaded tree,  the camera recorded the blue color of the light that is cast by the shade of the tree.

You may ask why this doesn’t happen every time you take a photo? Your camera actually has an automatic white balance adjustment built-in which automatically compensates for the differences in the color of light. Since it is a machine though it can sometimes be fooled by an object in your scene and actually choose the wrong white balance setting. Hence you get a photo with a blue color cast.

The auto white balance adjustment on your camera does a good job most of the time, but for the times that it gets confused, that’s when you switch to manual white balance. Most cameras will have a couple of manual settings that you can choose from:

– Sunlight  – use this setting when shooting in bright sunlight

- Overcast – use this setting when shooting on a cloudy day, it will add a little warmth (orange tone) to the photo

- Shade – use this setting when shooting in shady conditions, it will add quite a bit of warmth (orange tone) to the photo to counteract the blue cast caused by the shade

- Tungsten – use this setting when shooting indoors with tungsten lighting, it will add coolness (blue tone) to the photo to counteract the orange cast coming from the indoor lighting

– Fluorescent – use this setting when shooting indoors under standard fluorescent lighting, it will add a reddish tint to your photos to counteract the green cast caused by the fluorescent light

Each of the settings above will allow you to achieve a nice proper white balance when shooting under those various conditions. Luckily since you have a digital camera you can instantly see what effect each setting has on your image right after you capture it.

Does your photo look a little too blue? Try the Shade White Balance setting, that will add a bit more orange to it so your whites will look perfect. (Such as the image we shot above)

Shade Setting-cancels blue color cast

Subject looking a bit too green? Use the Fluorescent White Balance setting, it will shift the color a bit more in the red direction so your whites will look just as they should.

Did you happen to notice before how I said “since you had a digital camera”? Why is that? Remember when you used to shoot with film, there was no white balance setting on your film camera was there? That’s because when shooting with film the white balance setting is controlled by the film itself.

Actually the everyday, standard film you purchase at CVS or Walgreens is balanced mostly for sunlight. However, there are many specialty films that can be purchased which are white balanced for shade, tungsten, or even fluorescent.

So when shooting film you never had to worry about setting your white balance for each shot. If your camera was loaded with film balanced for shade you were pretty much stuck with it until you used up that roll of film. So with digital unlike film we have to worry about white balance for every shot, but it gives us better control and therefore better looking photos.

Now that we know how to set our white balance, what happens if you have a mixed lighting set up? For example, you’re shooting some photos indoors with both tungsten and fluorescent lighting, which setting should you use?

Well in this instance your camera can easily get fooled into using the wrong white balance setting. So the best way to deal with a situation like this is to calibrate your camera using an 18% gray card. “Hmm…” you say, “I seem to recall something about 18% gray when we learned about exposure a while back”.

Yes you are correct, when we talked about exposure we mentioned that your camera’s light meter tries to make everything in your image even out to a nice 18% gray. Your camera not only does this for exposure, it wants to do it for white balance too. Thus enters our 18% gray card..stage left, TA DA :)

There are many different companies that make gray cards for making sure your white balance is properly set. Below is an image of the one that I use from a company called Photovision. It not only helps you with your white balance but it helps check exposure as well.

18% Gray Card

Whichever one you choose to buy, make sure it is calibrated for digital cameras. Older gray cards, or ones made more for the film age are usually calibrated at 13% gray and will not work well for your digital camera. So you went out and bought an 18% gray card…now what do you do with it?

Aside from the white balance pre-sets we talked about above, most cameras have a setting that allow you to measure the white balance from what the camera sees. Sometimes this is called a manual white balance, custom white balance, or measured white balance. In this mode your camera will take a photo and then choose a white balance based upon the scene that it sees.

So to use your 18% gray card simply have your subject hold the card and then zoom in real close to it with your camera. The subject should hold the card under the same location and lighting conditions where you will take the final photo. Set your camera to the measured white balance setting and then snap your photo.

Since we know that our card is 18% gray, and your camera wants to make the white-balance of the scene in front of it measure 18% gray this will allow your camera to choose the perfect white-balance setting.

For example let’s say you’re shooting under shade. When your camera takes it’s measurement photo, the gray card will come out with a blueish color cast as we learned earlier. Therefore, your camera will shift the white-balance more towards the orange or warmer setting until the measurement photo measures 18% gray. Since the photo just happens to be of an 18% gray card we know that this will be the perfect white-balance setting for the scene we are about to shoot.

You only have to perform this calibration once for your scene. As long as you don’t change locations or change the lighting your new white balance setting will work perfectly for each and every photo you shoot under the same conditions. If you decide to move your subject somewhere else or your shade turns into sun, then simply re-calibrate your white balance with the 18% gray card again and you’re ready to shoot!

Some of our more advanced readers may be wondering if there is a way that they can set their white balance after they take their photo. Perhaps you’re not sure which white balance setting will work best for your scene. Or perhaps you have to shoot your subject very quickly and there’s simply no time to perform the calibration before you take your shot. Is there anything that can be done?

The answer is yes, if you shoot RAW. “Scott you’re talking crazy, these aren’t vegetables this is photography, what does RAW mean?” Shooting RAW means that the images that come out of your camera will look exactly the way that your camera’s sensor captures the scene.

Most digital cameras save their images as JPEGs. When this happens the camera does some processing of the image before it saves it to make the image look its best. But this is all very subjective, whose to say that the way your camera processes your image is truly the way you wanted it to look. This is where RAW comes in.

RAW means that the camera will save the image in it’s native format without any processing at all! This gives you unlimited creative possibilities with your photo. The down-side is that often times RAW images don’t look very good right out of the camera because no processing has been done to them. This requires you as the photographer to add some processing to the images to make them look their best. This can be a bit time-consuming.

RAW photo (left) vs Processed JPEG photo (right)

However, the upside is (and this is a good one…) that since no processing has occurred to the image, your image does not actually have any white-balance setting applied to it. So what does that mean in terms of our discussion. Basically it means that you are free to choose whichever white-balance setting you would like for your image, after you have shot the photo!

This is great, it means that you can try different white-balance settings to see what would work best for your scene. It also means that if you happened to choose the wrong white-balance setting when you shot the photo, you can get a do-over!

Let’s say when you shot that photo of your friend under the shade of that big tree you accidently had the white balance set to Tungsten. You will recall from our discussion earlier that a Tungsten white-balance setting will actually add more of a blue color-cast to your photo. This isn’t what you wanted, your photo already had a blue color-cast due to the shade of the tree; now your photo is really blue.

Of course if you shot RAW this is no problem at all! You can simply change your Tungsten white-balance setting to the Shade setting after you’ve transferred your photos to your computer. Your photo is saved, yay! You definitely can’t do that with a JPEG.

In conclusion exploring the many white-balance presets built-in to your digital camera will allow you to virtually eliminate any color casts you may find when shooting your photos. To nail the perfect white balance every time you should pick yourself up an 18% gray card and use it to calibrate your camera’s white balance before each scene change. And for those of you advanced shooters who want the ultimate in white-balance control, shooting RAW will not only allow you more control over your photos but also give you the opportunity to correct your white-balance mistakes long after you’ve shot the photo and gone home.

As always, please feel free to leave comments, ask questions, and share some of your results on this blog post.

Scott Dengrove is a professional photographer from the NYC area. Scott’s work has been featured in many national photography competitions and published in several nationally circulated magazines and publications. In addition, his work can currently be seen in 2 exhibits at Cosi® restaurants in the New York area. For more information, and to see more of Scott’s work visit his website at www.dengrovestudios.com and connect with him on his Facebook page at www.facebook.com/dengrovestudios