In a few of my previous articles, I stressed the importance of setting up your camera manually and ditching the automatic controls. Some of you might think I’m crazy. However, I’m willing to bet that the professionals in the audience would agree with me. As sophisticated as the new cameras are these days, there is still something to be said for being able to fine-tune your camera from shot to shot. It is something that I would hate to lose control over, because I know the damage it can do.  Remember, I’m an editor too. I have had to fix many mistakes from an operator that decided to let the camera “think” for itself. In my past camera articles, I have discussed the functions of the camera (both image and audio) in detail. Now let’s start breaking down each individual element and understand how (and why) they work.

Seeing white

I am going to begin this series with a little something that we all call white balance. I have found that inexperienced camera operators can go in one of three directions.  They either understand it completely, they become too over zealous and white balance every five minutes, or they forget about the white balance altogether. The last category is what we’ll primarily discuss today, although I will address the second category too because there is a point to white balancing too much. If you are simply interested in how to white balance a camera – skip below to the section “How to White Balance a Camera.”  If you would like to learn a little bit along the way continue below. I promise to make it easy to understand.

Color temperatures

In order to understand the concept of white balancing, you must understand what’s happening. We see with our eyes as a direct result of the way that light is reflected off of objects. This light comes from something called the electromagnetic spectrum. This spectrum contains various wavelengths of light, but the only range of this spectrum that humans can actually see is called the visible spectrum.

The visible spectrum is the portion of the electromagnetic spectrum that is visible to (can be detected by) the human eye. Electromagnetic radiation in this range of wavelengths is called visible light or simply light. A typical human eye will respond to wavelengths from about 390 to 750 nm. (Wikipedia)

If you’ve ever wondered why some lights, like normal lightbulbs, look different than others, like halogen bulbs, this chart will help a little:

First of all, I removed all of the technical information from the chart – like numbers and calculations – because I don’t want this post to get too daunting and technical.  (You can thank me later.) However, I do want to illustrate what is occurring naturally so that you can better understand how all of this stuff works.

There are two parts to the above chart. The top portion is an illustration of the entire electromagnetic spectrum. As you can see, it contains all the cool sci-fi stuff like gamma rays and x-rays on the right hand side and radio waves over on the left hand side.  In the middle of all of this is the portion of light that we can see – illustrated by the bottom portion of this chart.  This is the visible spectrum of light and it directly effects how our cameras (and our eyes) see color – so let’s focus on this for a bit.

The visible spectrum

As you can tell from the chart, the frequency of the wavelength effects the color of the light – lower frequency produces an orange color, higher frequency produces a blue color. For example, if you look at a room lit by tungsten lighting (a standard light bulb) compared to a room lit by daylight (natural sunlight) you will notice that the tungsten room will have an orangy-red color, while the daylight room will appear more blue. Now, if you were to walk from the tungsten room to the daylight room, chances are you will not notice much of a difference with your eyes.  However, if you do a side-by-side comparison you will definitely see the color change. This is because our eyes do a fantastic job of “white balancing” for us. Cameras, on the other hand, need to be told what is white.

Measurement of the color

Within the visible spectrum of light you have colors that range from orange to violet. The change from color to color is continuous and therefore would be hard to define by names alone – unless you like saying “green,” “slightly less green,” “slightly slightly less green with a hint of yellow” – so scientists and engineers came up with a way to measure the frequency and supply us with a named scale.  They called it the Kelvin scale, which is named after William Thomson, 1st Baron Kelvin (or Lord Kelvin.) He is known for developing the basis of Absolute Zero and so they honored him by naming a unit of temperature measure after him. Its namesake is probably not too important to you – however, the Kelvin scale is important to you because you will use it every time you white balance your camera.

The Kelvin scale measures the temperature of light and assigns a numerical value for each color.  Shorter wavelengths have a lower temperature, while longer wavelengths have a higher temperature. What does this mean to you? When you white balance a camera, you are selecting a numerical value (from the Kelvin scale) that corresponds to the type of light in your setting.  Balanced studio lights will give you a measurement of 3200 K (Kelvin) and sunlight will give you a measurement of 5600K.  Sometimes this is represented as 3.2 K or 5.6 K but the idea is the same.

White balancing the camera

You should have a good understanding of the theories involved, so now it’s time to put those to good use.  To white balance a professional camera you will need to be aware of three elements:

The front of the camera (just under the viewfinder) is where you'll find the AWB/ABB switch for white balancing

The white balance/black balance toggle switch (labeled AWB/ABB) is on the front of the camera. You push the toggle down to Black balance your camera – this should be done at the beginning of your shoot day – and you would toggle up to set your white balance.

Camera controls on the operator side - the Preset/A/B white balance switch is on the far right

The Preset/A/B switch allows you to choose a Preset white balance or set your own manual white balance and store them in either the “A” setting or the “B” setting.

Filter wheel on a Panasonic HPX 500 Camera

and the filter wheel.

There are two ways to handle white balance, preset and manual.  The preset white balance uses standard settings for daylight, tungsten and sometimes a mixture in-between.  If you know the white balance of your setting, you can just select the proper filter, set the white balance switch to Preset and start shooting. “Where do I select the proper filter?” you might ask.  Well, the filter wheel, of course.

The filter wheel

Most cameras have a filter wheel – located near the viewfinder on the operator’s side of the camera – that rotate a series of filters in between the lens and the sensor on the camera. These filters compensate for the different types of lighting (daylight, tungsten) that occur in our set ups. Think of it like this; if the camera’s sensor is balanced for daylight (5600 K) but you are inside under studio lighting (3200 K)  you need to correct the color. You would use one of these filters to compensate for the change in color temperature. Common filter wheels will have:

• “1″ setting – for 3200K and no neutral density
• “2″ setting – for 5600K and no neutral density
• “3″ setting – for 5600K and 1/4 neutral density
• “4″ setting – for 5600K and 1/2 neutral density

On more elaborate (and expensive) cameras, you will find a dual filter wheel.

Dual filter wheel on a Sony Betacam SP camera

This gives you control of color correction filters AND neutral density separately. The outer ring of the filter wheel controls the ND filters and the inner ring controls the color correction:

• “A” setting – for 3200K with cross filter
• “B” setting – for 3200K no cross filter
• “C” setting – for 4300K
• “D” setting – for 6800K

In case you were wondering, the cross filter provides a star-like effect to points of light in the frame. You will see this a lot on wide shots of sets or wide shots of sporting events. There is a cross-hatched design in the filter that makes points of light form a star pattern.

Preset white balancing

To use a preset setting, simply choose the proper filter for your setup on the filter wheel.  If you are outside, use a daylight filter.  If you are inside under tungsten lighting, use a tungsten filter.  After you choose your proper filter, select Preset on the Preset/A/B switch.  It’s that easy.  The hard part is knowing what filter to use – daylight is not always daylight.  Cloudy conditions will give you a different white balance than direct sunlight and mixed florescent and tungsten lighting will also give a different reading than preset tungsten.  This is where that thing called practice comes in to play.

Manual white balancing

Preset white balance will work only so far, however, so it is always a good idea to manually select a white balance. For this we will use the “A” and “B” setting on the Preset/A/B switch. Here’s how it works – we’ll use a studio set-up with tungsten lights as our example:

• Choose the appropriate filter on the filter wheel. Since we are in a studio with studio lighting, we’ll select “B” on the filter wheel because it is 3200K and our tungsten studio lights are also 3200K.
• Select either the “A” setting or a “B” setting on the Preset/A/B toggle switch. I’ll choose “A.”  Each of these hold manual white balance information so that you can have two designated white balance settings. This is helpful when you have to move between rooms and the white balances are different.  It gives you a chance to set one balance in the “A” setting and another in the “B” setting.  As long as you remember to switch them when you move from room to room, you’re golden.
• Find something white. This can be a white card (they come with your camera or camera case) a set of warming cards or something like a white t-shirt/piece of paper/table cloth, etc. (Make sure that whatever it is, it’s white – not off-white, not grey . . . WHITE)
• Fill your camera’s frame with the white object and make sure that you are getting the proper lighting on the white card. You’ll want someone to hold the white card in the position of your talent or in the position of the main subject.
• Expose the white area properly. Make sure that your exposure is correct on the white object so that you can obtain a good reading.
• Toggle your camera’s AWB/ABB switch toward the AWB section – usually an upwards toggle -  and wait for an indication that the reading is successful.  It will usually give you a reading – in this case it should be around 3.2 or 3.4 depending on your lighting

You just successfully white balanced your camera.  I’m so proud. Remember that if you control your white balance manually, you can fine-tune the look of your final image. Many directors of photography will spend a great deal of time and effort to achieve a proper white balance on set.

Prosumer cameras

Most prosumer cameras will have the same functionality as their professional brothers – the settings are just in different places.  Refer to your manual to find the exact location of your white balance functions but still use the principals above.  The only thing missing will be the filter wheel – that happens to be unique to professional cameras.  Some cameras, like HD-SLR cameras, only allow you to use preset white balances. Instead of using numerical values like 3.2 and 5.6, they use pictures so that should make it easier. Look for an upcoming post about prosumer white balancing.

Final review

This might seem like a long post but it is important that you understand what is happening when you are hired to run a camera. Your job is to produce quality video and deliver that video to an editor. It is your job to provide properly color balanced images – not to have someone “fix it in post.” So make sure that you’re aware of a few things:

• Always be aware of your environment and know where you’ll be shooting. If your producer wants you to move from room to room, find out exactly which rooms you’ll be moving to and set up your white balance ahead of time.  This is why the manufacturers give you two white balance settings – A and B.
• Bring something white with you at all times. If you don’t have access to a true white card, get one. You can pick up warming cards, you can create a white card from some cardboard or you can follow this tutorial for adding one to your lens cap.
• Make sure you understand what the filter wheel is doing. You might not have a filter wheel similar to the example above so make sure that you understand what you do have. Some wheels only have 5.6 settings and 3.2 settings. This means that you’re either balancing off of daylight (5.6) or tungsten light (3.2) when you’re setting your white balance.
• Fill the screen with your white card. The white object should fill most of your frame in order to get a proper reading. If it does not, you will get a bad reading.
• Expose the white area properly. After filling the frame with the white object, you want to expose the camera for the white. If you are underexposed or overexposed the camera will usually tell you by displaying a status message. For example, “WB NG – Low Level” – whenever you see “NG” anywhere it’s a bad sign.  NG – No Good.
• Double-check your reading. If you’re outside in daylight and you get a 3.4 reading, something’s wrong. This is where you need to know what you’re doing. Usually when you get a bad reading like the one here, it’s because your white card is not in the proper spot and might be reflecting a strange color temperature. Spend time getting used to the Kelvin scale and how it corresponds to different lighting. At the very least, understand the difference between daylight and tungsten light. (Having a monitor nearby doesn’t hurt either.)

After a while, this will become second nature to you. I know that I can tell the difference in the color temperature of a room almost immediately, but it took me quite a while to do so.  Like anything else in this business, it takes practice to be successful. Keep practicing and you will do well.