Different types of light conditions have different colour temperatures. If you take a photo using tungsten lighting (your usual light bulbs) you’ll notice that the whole picture will have a yellowish tinge to it. If you take a photo in fluorescent light, it will have a bluish-green tint to it. These are colour casts. Sometimes, for a visual effect, the photographer will desire a colour cast, and shoot at particular times of day to obtain this. For example in the hour after sunrise and the hour before sunset, they might make use of the ‘golden hour’ for the particular warm glow that is achieved in photographs at those times. However, an hour before sunrise and the hour after sunset will achieve a colder, blue colour cast – great for making a cold day look even colder.
However, if you’re photographing people, they’re not going to look their best in blue light. It makes them look like they are the walking dead and similarly, you could make them look quite jaundiced with warmer colour casts. If the lighting produces tints that you don’t want, then the photographer will aim for ‘white balance’ in the shot. This means to effectively remove the colour cast.
You could spend some time post-processing to remove the colour cast as I have done with the photograph I took last week:
And here it is with some of the colour cast removed with post processing:
In the process of correcting, it was difficult not to introduce a different colour cast and truly achieve white balance. If I’d played for longer, that white cloth might eventually look white.
But isn’t prevention better than cure?
If only I knew how to adjust the white balance of my shots without using an automatic mode on the camera!
Sometimes there are good reasons to go read that manual. Heading to page 89, I find there are several options from using in-built settings to creating and storing my own white balance adjustments. The easiest however might sound the most complex.
Colour temperature is measured in Kelvins. The higher the kelvins – the colder the photo will appear. 5000 K is the temperature of ‘white light’. By going choosing the Kelvins option, I can just rotate a dial to create the desired compensation. So with the blue colour cast as seen in the glasses above, by inputting a high Kelvin setting that reflects that cast, the camera then makes the adjustment to produce better white balance.
Play around with colour cast. Take photos in different light conditions, both natural and artificial. Note how the colour tint in the image changes.
If you have a camera with more control, investigate how to correct colour cast and obtain white balance. Have a go!
I chose this quaint figurine to photograph indoors, using natural light. My aim was to create images requiring no editing in photoshop, to minimise time. I set the WB meter to three different settings: roughly 2500, 5000 and 7500 K, producing two photos with colour cast and one with white balance. The difference is most visible in the ‘whites’ of the image.
Image perfect? Hmmm, well, you’ll notice the whites, particularly in the background are quite bleached. However the front of the figurine was shadowed from the light. Some over exposed and underexposed parts. We’ll talk exposure in the next challenge and ways to deal with these issues.
Let us know how you get on with the challenge, if you’re following. I’m feeling happy I’ve learned something new!