In this article we'll cover how to properly set a custom white balance manually in your digital camera. First, a little easy to digest explanation of why you need white balance though. Light sources emit color in different temperature ranges referred to as kelvin. Without boring everyone out of their mind, I use this following example to explain the difference of kelvin, which will later explain why we need to adjust for it.
Street lights typically emit an orange color to them, when you take photographs with your digital camera in auto mode, the orange gets over-exaggerated and the end result isn't so pleasing. This is typically considered warm lighting.
On the other end of the spectrum is cool lighting and favors the blue / white kelvin spectrum. The new Lexus, BMW, Mercedes headlights all have this white / blue light to them.
In both examples, light is the final result, but the color is different. In days gone past when film ruled, it was much more lenient towards these particular color shifts and two main types of color film existed, regular and tungsten. While gels could be used in extreme cases, these two film types satisfied the needs of most everyone; digital sensors however completely changed the game.
Almost all digital cameras come with a handful of preset white balance modes, each usually has an indicator to get you in the round-about territory of where you should be, plus auto which isn't all that great. The preset modes are great when you are 100% sure of your lighting, but how often can that be? Setting your preset to Sun mode for example doesn't account for the light change from the early morning, high noon and late afternoon. Likewise, most homes have multiple different temperature bulbs, that makes it near impossible to use a preset to get an accurate white balance. The goal for white balance is to achieve a neutral and accurate portrayal of what the naked eye sees and to represent that into your photography.
Setting a manual white balance, often called a custom white balance is actually way easier then most people could ever hope it to be. You'll want to shoot a custom white balance in any situation that you cannot control the light sources being used.
To do so, all you need is a grey card and the understanding of how your camera handles custom white balances. For most, it will involve taking a photograph in the lighting you are shooting in of an 18% gray card.
In the example above, a model is holding the gray card and this is for display only, you'll want to fill the frame with the gray card and ensure you have a properly exposed image. You can check your exposure setting either using a light meter or using the histogram feature review in your camera, looking for a solid spike right in the middle of the graph.
Once you have the image captured, most cameras have a menu option that will allow you to recall that image and set it as the custom white balance, and then will instruct you to change the preset to the proper custom white balance setting.
There's no magic, it's really that easy! There is one secret though. You want your gray card to be where your focal point is. That is to say, the model above is holding it directly over their face, that's what is important. If you, the photographer, are standing 15 yards away and simply hold the gray card in one hand, camera in the other and shoot it, the light falling on the gray card for which you make your custom white balance setting could differ from what falls on your subject. You must get the gray card into the frame with the subject!
The added bonus to doing a custom white balance, resulting in more neutral and natural colors is the total decrease in post production work you'll have adjusting for improper white balance settings.