Color Temperature – A balancing act

Introduction

This time I am going to address the more intermediate topic “White balance (WB)”, however I am also going to throw in a more advanced tip when it comes to Fluorescent lighting. You might argue that WB is of less importance when shooting RAW, while setting doesn’t affect the actual image data in the RAW file. But it does affect the image displayed on the camera’s LCD. Moreover is there embedded a JPG in every Raw file (Sony Alpha A99 contains two embedded jpg’s 1616×1080 pixels and 160×120 pixels), the embedded JPEG is used to display histograms and over/under-exposure warnings displayed by the camera. This JPG is affected by the WB setting.

You can set the white balance to automatic, and hope for the best, or choose a manual preset to match the conditions. In most cases will Auto White Balance be close enough, in order for getting the embedded JPEG right and allow for all the things the camera does with it. But not always! When shooting out of the cameras comfort zone, like when shooting Aurora Borealis or deep shadows, then it is worth adjusting the setting manually.

This post do not trouble itself with grey cards J should you be interested in grey cards to find info here.

White Balance Quantified

The color temperature is quantified in degrees of Kelvin. It varies from temperature between 2,000 degrees Kelvin (warm) to 9,500 degrees Kelvin (cold). Low-temperature is in the spectrum red/yellow, while high-temperature is in the colder blueish tones. Your camera features named presets; which are corresponding to specific conditions, such as daylight, tungsten, and shade. They are ok indicators of certain situations, but really far from good enough, while the right setting often is between these fixed intervals.

• Auto – The Auto setting helps in adjusting the white balance automatically according to the different lighting conditions.
• Tungsten – This mode is used for light under a little bulb like tungsten, and it is often used while shooting indoors.
• Fluorescent – This mode is used for getting brighter and warmer shots while compensating for cool shade of fluorescent light.
• Daylight – This mode is for the normal day light setting, while shooting outdoors.
• Cloudy – This mode is ideal for while shooting on a cloudy day. This is because it warms up the subject and surroundings.
• Flash – The flash mode is required when there is inadequate lighting available.
• Shade – A shaded location generally produces cooler or bluer pictures, hence you need to warm up the surroundings while shooting shaded objects.

As you see these presets is rough cut, and might serve as starting points, but adjustments has to be made from there.

• The light at dawn and dusk is magical. The light changes rapidly at sunset or dawn. Characteristic colors of yellow, orange and reddish tones are desirable. To achieve this, can settings easily gets as low/warm as 2,400K. As the light climbs during the morning, and falls towards evening. Will the light still have a treasured warm glow; 4,000K temperature will approximately be the setting that you will be looking for.
• Noon sunlight produces neutral colors. I personally dislike this light, due to the angle of the light. Settings around 5,500K will yield the best results. You might notice that many flashes claims to produce “Neutral light” I find this to be farfetched, as flashes often produces a cooler light. I generally prefer and overcast sky. It slightly ‘cooler’ than direct sunlight. To counter this set your settings around 6,000K. But it can be even cooler; Deep shade produces a very cool lighting where you will aim for 6,500K. Should you be in an open shade on a sunny day, then trouble is a head. It will lead to col looking photos unless you compensate with settings at 7,500K.
• When shooting under Fluorescent lighting, you might have noticed that you are not getting the full spectrum of colors in your images. Colors may display with a green, yellow or even red tinge. And then there may be an absence of magenta. You might see fluorescent light as close to white with your eyes but this is very far from the truth and the brain compensates nicely to fool us. Taking photos of Fluorescent light is a little tricky to say the least. You might think choosing Fluorescent preset will compensate for the cooler shade or you might think you will be able to fix the WB in post-production; sadly this is not always the case, especially with fast shutter speeds. Fluorescent lights use what is called a ballast to regulate the flow of current. This system is what causes a cycling varying the colors over given time. The USA operates with a 60 pulse per second cycle, where we operate with a 50 pulse per second pulse in Europe. To compensate to this you need to set your cameras shutter to be slower than this cycle, to get the full spectra of light emitted from the light tube. In the USA for example using an exposure of less than 1/60sec means you will only capture a partial gamut of colors!
• Be careful not to judge Domestic tungsten to be the same as Photographic tungsten. Domestic lighting wave length is orientated towards stronger wavelengths yielding a strong yellow/orange cast. Don’t be surprised that you have to be lower than 3,200K, depending on the bulb type. Photographic tungsten lighting is cooler and more neutral than domestic tungsten lighting. It will still produce warmer light than daylight. Where the domestic tungsten was more yellow/orange, will photographic tungsten be more yellowish. Adjust the camera’s white balance to around 3,400K.