We strip through the jargon to break down colour temperature — what it is, what to look out for, and how to ensure you’ve got it right, every time
The D-Photo team talks through colour temperature — and how to ensure you’ve got it right, every time
The technical definition of colour temperature is full of terms such as the ‘Planckian curve’, or ‘chromaticity space’ — in short, it’s very confusing, a wee bit stale, and leaves most feeling even more baffled than before. It’s for this reason that many photographers stick to Auto White Balance, even when they might otherwise work exclusively in manual modes.
In layman’s terms, colour temperature describes the way in which different light sources produce different-coloured light, due to the various proportions of the three primary colours — red, green, and blue — that form white light. A candle emanates a warm, orange glow, for example, while the rays of the midday sun on a clear day emit a bluish tint.
When the colour temperature is high, more blue light exists, and when the colour temperature is low, there’s more red. These different colours can be expressed using a number, measured in Kelvins — a term that you probably came across back in your high school science class, but have probably long forgotten. The scale is an extension of the Celsius scale, based on the colour of the light, and was conceived by determining the colour of a black-body radiator as it heated to varying temperatures. At lower temperatures, the chunk of metal glows red, then orange, then yellow. As it gets hotter, the metal turns white, and at its hottest, it emanates blue. This change in colour is what we use as a basis for the colour temperature of light in photography.
So, why does any of it matter? Well, while the human eye adjusts continually to changing light conditions, digital cameras are simply not as good at adapting chromatically, nor are their sensors quite so lenient. Instead, cameras handle colours by identifying the colour cast, then adding the same amount of the opposite colour to try and create a neutral image, where whites look as white
as possible. This is your white balance setting, and if you are recording any format other than RAW, this setting permanently determines the colour balance of your recorded image. Though Auto White Balance yields great results in daylight situations, it doesn’t do quite so well in low light, or mixed lighting (where it tends to produce an average). As a result, images are sometimes unwittingly drenched in a colour cast — that is, an overall blue or orange tint.
So, if you’re tired of finding that your images are veiled in an unnatural hue, if you want consistency in colour across your images so that it’s easier to make batch edits or sync through its settings or dial in your Kelvin temperature, and experiment with how white balance affects images in real time via the camera’s back LCD screen. The medium-format mirrorless Fujifilm GFX 50S boasts a 3.2-inch 2.36m-dot touchscreen LCD that’s also available for image playback, menu navigation, and live view shooting. This LCD features a unique tilting design which moves both 45 degrees downward and 90 degrees upward for shooting from high and low angles, and it tilts 60 degrees to the side to benefit shooting in the vertical orientation when in live view. Plus, with several dedicated dials for adjusting exposure settings, and a top LCD screen that settings across the board, or if you want to shoot true, accurate colour — here’s where manual white balance comes in.
The Kelvin temperature scale for photography most commonly ranges from around 1700K to 9000K, so keeping some key values in mind will also go a long way. In short, incandescent light is 3200K, white fluorescent light is 4200K, sunlight is 5500K, daylight with cloud cover is 6000K, and shade is 7000K.
The quickest way to get your head around manual white balance is to turn your camera’s live view mode on, click displays white balance and exposure data, the GFX 50S makes manual easy.
Further ensuring that nothing comes in the way of exact image rendition, the heart of the GFX camera system boasts a 43.8 x 32.9mm 51.4-megapixel CMOS sensor, which pairs with the X-Processor Pro image processor to produce an extremely wide dynamic range and high resolution, as well as an extended sensitivity range of ISO 50, right through to a massive 102,400.
To find out more about the imaging capabilities of the Fujifilm GFX 50S, head to fujifilm.co.nz.