CAMERA FEATURES

White Balance: definition and settings

Find out about White Balance (WB), all the WB settings on your camera, how to use them to get accurate colours, and why you don't always need to worry about doing so.

The human eye achieves an impressive dynamic range, automatically adjusting for the lighting conditions so we can see in very bright light as well as in gloomy locations. The eye and brain in partnership can also correct colour casts so that a white piece of paper, for example, is perceived as white, regardless of the ambient light.

Unfortunately, digital cameras are not so clever. They record the scene as they see it, within their limitations. This is why, in tricky lighting conditions, we have to set the white balance to ensure the result we want. It is also why we sometimes have to tell the camera the colour temperature of the light falling onto the scene.

What does this mean? In simple terms, light is made up of the three primary colours − red, green and blue. In theory, an equal intensity of all three produces white light, but in practice these colours are present in different proportions in light from different sources. For example, tungsten-filament lights produce illumination with more red than fluorescent lights, which create greener light. Of course, natural light also varies according to the conditions, so that colours appear warmer (more red) at sunset and cooler (more blue) at midday. This varying proportion of colours can be expressed as the colour temperature, which is measured on the Kelvin scale (more about this shortly).

If you are shooting images in any format other than RAW, the camera will post-process the image to make the colours in the scene as accurate as possible. However, this is not always as easy as it seems − the colour temperature of the light falling onto the scene affects the way the camera sees the colours and, unlike our brains, it does not automatically correct it. For example, with no correction, a white wall photographed under tungsten lighting will appear very yellow, and under a fluorescent light will look very green. This is why all digital EOS cameras have the option to set the white balance to suit the ambient light.

If you shoot RAW files, you have complete control over colour in post-processing, so the white balance need not concern you at the time the exposure is made, although it can be useful to get things close to the final image because this will enable you to properly assess the images you're capturing.

Bath Abbey, England, photographed using Auto White Balance, resulting in warm orange colours.

This scene photographed using the Auto White Balance setting exhibits very warm colours, thanks to the floodlights illuminating the building.

Bath Abbey, England, photographed using Custom White Balance, resulting in cooler colours.

Changing to a Custom White Balance setting results in an image with truer colours, particularly in the stonework of the building.

What do the white balance settings mean?

Canon cameras have several white balance settings, and your choice of these depends on the type of light you are shooting in.

White Balance Setting

Description

Auto White Balance

You can use this setting as a default in most straightforward lighting conditions. Auto White Balance works by evaluating the scene and deciding the most appropriate white point in it. The setting works reasonably well if the colour temperature of the ambient light is within the range of about 3,000–7,000K. However, if there is an abundance of one colour in the image, or if there is no actual white for the meter to use as a reference, the system can be fooled, resulting in an image with a colour cast.

In 2016, Canon introduced two versions of Auto White Balance: Ambience Priority and White Priority. Ambience Priority is the default, and the AWB method used in earlier Canon cameras. It is useful when you want to retain a little of the warmth of artificial lighting. In White Priority mode, however, the camera will attempt to remove any warm cast from the image so that any whites are pure white.

Daylight

Use this setting if you are shooting in bright sunshine. It's designed for a colour temperature of around 5,200K, which is actually very slightly cooler than noon sunlight. However, even if you rarely actually shoot at noon, this setting will work well for much of the day.

Shade

Although we describe shaded areas as colder (bluer), the way the Kelvin scale works means the colour temperature is actually higher, usually around 7,000K. This setting is most suited to areas of gentle shade rather than very heavy shadow.

Cloudy

This sets a colour temperature of around 6,000K. It is best used on days when the sun is behind the clouds, creating a very even and diffused light but a little warmer than Shade.

Tungsten

The first of the artificial lighting settings, this assumes a colour temperature of around 3,200K and is suitable for most tungsten lamps, which normally emit a yellowish light.

Fluorescent

The second artificial light setting is set for around 4,000K, the approximate colour temperature of fluorescent lights. The problem with fluorescent lights is that there are several types, each with a different colour temperature, and they also change over time, gradually altering the colour temperature of the light they emit, so this setting might not give perfect results in all cases. Fluorescent lights also emit an interrupted spectrum with peaks over quite a wide range. Canon's flicker detection feature is available in some EOS cameras to address this.

Flash setting

For use with either a built-in flash or Speedlites. Flash is a very white light with a colour temperature around 6,000K, although this might be fine-tuned to match if you're using a Speedlite with a colour transmission function.

All these settings still rely on the camera doing some calculations to obtain the correct colour balance. However, there are two further settings which give you total control.

White Balance Setting

Description

Custom White Balance

This option enables you to instruct the camera which area in the scene is supposed to be a neutral white. The camera can calculate the colour shift required to make that surface white. It then applies that shift to all colours in the scene to provide a correct colour balance to the image, whatever the lighting. More about this shortly.

The EOS-1D X Mark III, released in 2020, allows you to store up to five different Custom White Balance settings and give them names or captions to make them easy to identify so you can select between them quickly.

Kelvin

Many EOS cameras have this option, which enables you to set the colour temperature in degrees Kelvin in 100K increments from 2,500K to 10,000K depending on the camera model. Most photographers set the Kelvin value by eye and based on experience, but you can also use a dedicated colour temperature meter to suggest the appropriate setting.

If you have a colour temperature meter then the Kelvin setting may be the best one to use, because you can set the exact colour temperature shift needed. But remember, if you do this you will need to take a few test shots to calibrate your colour temperature meter with the camera's meter.

A portrait of a woman wearing a grey pullover, divided into eight vertical strips, each with a different White Balance setting.

The colours in your image, particularly skin tones, can look strikingly different under different White Balance settings. From left to right: Auto White Balance (Ambience Priority), Auto White Balance (White Priority), Daylight, Shade, Cloudy, Tungsten, Fluorescent, Flash.

Two versions of an evening shot of a building, one with warm orange colours and the other with pure whites.

Auto White Balance (Ambience Priority) retains the warmth of artificial lighting. By contrast, Auto White Balance (White Priority) is designed to render white as pure white.

Setting a Custom White Balance

It is possible to use the Auto White Balance setting for all your shots and let the camera sort out the light, or to select the white balance symbol appropriate to the lighting conditions. However, no matter how good these settings are, they won't produce the perfect white balance in all situations.

Instead, use the following procedure and you will end up with images that are properly white-balanced – but bear in mind that if you're outdoors, the light changes constantly, and you need to repeat the procedure whenever lighting conditions change or you move to a new scene.

Understanding colour temperature

Colour temperature is measured in degrees Kelvin (K). The Scottish mathematician and physicist William Kelvin proposed the absolute, or Kelvin, scale in 1848. This scale uses −273.15°C as its zero point or "absolute zero". Confusingly, the Kelvin scale runs in the opposite direction to the scale on a thermometer, so warm colours (red and orange) have lower numbers, around 2,000–3,000K, while cool colours (blues and greens) are at the higher end of the scale, around 20,000K. Neutral white light is 6,504K.
You need a sheet of white paper, or a mid-tone grey card. With your scene and lighting arranged, place the paper or card in the scene. Making sure that the white card covers at least the centre circle marked in the viewfinder, take a shot. The autofocus may have trouble focusing on the flat card, so focus on the edge of the card and then recompose, or switch to manual focus.

Next, select Custom WB in the menu. From the Custom White Balance screen, find and select the image you shot in the previous step. The white balance data from the image will be imported.

Exit the menu, then select Custom White Balance from the white balance settings. The pictures you shoot will now be balanced to your test image.

On the EOS-1 series cameras, the menu is slightly different. Within the Set Custom WB screen there are options to Select image on card (the same as above) or to Record and register WB – this assumes you have not yet captured an image to take a Custom White Balance reading from. If you select the second option, then take a picture, the camera will immediately read the image and set the white balance accordingly.
In a shot with a warm colour cast, a white carnival mask with gold patterning and scarlet headdress appears cream-coloured but richly detailed.

Accurate colour rendition is not always the goal. In this indoor photo, the artifical lighting has produced a warm colour cast, but this brings out the golden tones and rich scarlet hues of this carnival mask.

In a colour-corrected version of the same shot, the carnival mask appears white but other colours are dulled.

By contrast, correcting the colour cast so that the white areas of the mask are true white has left the gold and scarlet colours looking duller, and some of the background colours a little washed-out.

White balance bracketing

If you find you still cannot get the perfect colour balance in-camera, then EOS digital cameras from 2003 onwards have a white balance auto bracketing function. This allows you to bracket the white balance setting in the same way that you can bracket exposures. You can select the level of change between the images up to ±3 steps in full-step increments. The images are then recorded in this sequence: 1 = set colour temperature, 2 = cooler/bluer colour, 3 = warmer/redder colour.

With all these options, it is possible to obtain a completely neutral tone in most shooting situations. However, this may not always produce the most attractive images. At a carnival, for example, there is likely to be a diverse mix of light sources − tungsten giving a yellow glow, fluorescent adding some green, and lots of neon lights. Even if you were able to balance all the light sources present, the result could end up looking very clinical and fail to convey the fun, warmth and atmosphere of the show. So do not always assume neutral is best − and don't worry too much about getting white balance spot-on in-camera especially if you are shooting RAW.
An interior shot with a warm colour cast being corrected in DPP.

Canon's Digital Photo Professional (DPP) software has a range of powerful tools for correcting colour casts, from one-click quick fixes to precise colour temperature adjustment and advanced colour balance controls.

Working in RAW format

If you've set your camera to save JPEGs, the camera applies the white balance settings as it processes the image, before saving it to your memory card. Although you can adjust colour in your image editing software afterwards to some extent, the WB setting is "baked in" and strong colour casts are difficult to remove. By shooting in RAW format, you avoid this in-camera processing, and the image saved on the memory card is exactly as captured by the CMOS sensor. It is then up to you to adjust the white balance in your RAW processing software.

Canon's Digital Photo Professional (DPP) software offers a range of powerful options for doing this. You can use the Click White Balance eyedropper to click on an area of the image that should be white or a neutral grey, and the colours will be adjusted with reference to that; you can use the Colour Temperature slider or specify the colour temperature in degrees Kelvin; you can adjust the Blue-Amber and Magenta-Green balance using sliders. Similar tools are widely available in other RAW processing software.

One of the advantages of shooting RAW files is that you can apply different white balance settings to the image in order to see which give the most natural, or most attractive, results. The original RAW file remains unchanged. This means you can return to the RAW file and try again if the initial results are not what you want, or produce variants of the image with different feel and atmosphere.

Autor Angela Nicholson


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