Counteract Colour Casts

George Cairns explains how to warm up or cool down colour casts by using white balance presets and custom adjustments in Capture NX-D

Different light sources have different colour temperatures. As a result it can be a challenge for your Nikon to capture accurate colours. For example, tungsten bulbs add a warm orange colour cast to the subject, which can make skin tones look too orange. Daylight, on the other hand, will produce a cooler cast, bathing the scene in a wash of blue.      
Your Nikon's Auto White Balance (AWB) setting attempts to counteract these warm or cool casts, by cooling down or warming up the image until white areas are free from any hint of orange or blue. Once the whites are balanced then all of the other colours should look more natural. However, sometimes the AWB operation is less than successful. You can give your Nikon a helping hand by choosing a white balance preset that matches the lighting of the location. They do a great job, but may struggle with mixed lighting conditions, such as those in our image.

"Once the whites are balanced then all of the other colours should look more natural"


Correcting Colour Casts

Where to Get capture NX-D
It's made for Nikons, and it's free!
Capture NX-D is available as a free download from Nikon at http://nikonimglib.com/ncnxd As new Nikons are introduced, Capture NX-D should be the first software to support them
.

 

Step by step: balance mixed lighting
Use white balance presets and the Color Temperature slider for whiter whites

1 Crop the shot


Use the Folders window to browse to our colourcast_ start.NEF file. Use the Crop tool to crop to a square (1:1) aspect ratio. On Auto White Balance the camera has balanced the colours for the distant sunlit subject. As a result the colours in the shadows look too blue.

2 pick a preset


Go to the WB (White Balance) drop-down menu in the Edit panel. Try the Daylight WB preset. The Color Temperature slider moves up to a slightly warmer 5200K. The Daylight preset suits the warm sunlit tower in the background, but the shaded foreground is still too blue.

3 Warm it up


Try the Shade preset from the WB drop-down menu. This pushes the Color Temperature slider up to 8000K, which warms up the cold blue colours in the foreground shadows to make their whites look white. However, the colours in sunlit areas now look too warm and yellow.

4 Find a balance


Due to mixed lighting conditions a preset will only get us so far. We need to find a compromise in our colour correction. Go to the Color Temperature slider and drag the slider left to reduce the golden hue of the sunlit areas without cooling down the shadows too much.

Custom white balance


By combining white balance presets with a manual tweak of the Color Temperature slider you should be able to get your colours looking balanced and more natural. If you're not sure which WB preset to use you can grab the Gray Point Sample tool from the toolbar and click on an area that should be white or neutral grey. If you click on the foreground girl's white dress the Gray Point Sample tool will detect a hint of blue in this shaded area. It will then warm up the sampled area until the whites of the dress are a neutral white. This will correct the colours in the rest of the shot at the same time.

 

Expert Tips

Perfect presets
White balance presets are very effective, though you need to remember to change them manually or they can cause very noticeable colour casts. For example, if you shoot indoors with a Tungsten preset, the camera will cool down warm orange colours. If you wander outside and forget to change the WB preset, then the camera will make cold blue daylight look even colder and more blue. Fortunately you can fix these types of white balance errors with ease in Capture NX-D.

Degrees kelvin


The colour temperature of light is measured in degrees Kelvin (after the physicist Lord Kelvin). An incandescent lamp emits light with a warm temperature of 2800K, whereas direct sunlight has a cooler colour temperature of around 5000K. Capture NX-D has a colour-coded slider based on the Kelvin scale. You can slide it to the left to cool down a shot, or right to warm it up. Some of the white balance presets in the drop-down menu also refer to a precise Kelvin value (such as Fluorescent 3000K).

Add new comment

By submitting this form, you accept the Mollom privacy policy.