Friday 25 April 2008

Using flash, part 6 - flash colour temperature

For further photography-related information check out my compendium of tips.

Light from flash units is typically balanced for noon daylight (5600K) - if this means nothing to you then check out an overview of colour temperature at ePhotozine. Summer sunlight from 9am to 3pm is in the range 5400-5700K, so using your flash as a fill-in light during this time leads to a good mix between ambient and flash light. When you use your flash indoors and capture ambient light produced by tungsten lightbulbs (2800K), however, it's impossible to adjust the white balance of your shot correctly for both light sources. If you set the white balance for the flash light, the ambient light will appear orange, setting correctly for the ambient light means the flash light will appear blue. To overcome this you can adjust the colour temperature of your flash using filters - I purchased a great selection from The picture above shows three types of filter: colour temperature orange (CTO - for cooling the flash light to balance with the light from tungsten lamps), colour temperature blue (CTB - to warm the flash light) and plus green (adds a green cast to balance with fluorescent lighting). These can be attached to the flash unit using velcro, but having watched Blue Peter during my formative years, I'm naturally a dab-hand with cardboard, double-sided sticky tape and scissors (provided an adult is available to supervise me) and so constructed a filter mount. 

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