Each light type has its own colour temperature (the redness or blueness of the light, where redder is “warmer”, and more blue is “colder”, in photographers’ terms). This colour is expressed as a temperature, which is measured in degrees Kelvin (after Lord Kelvin). Physicists and engineers know this.
Our cameras need to adjust to the light’s colour temperature. In the film days we used to do this by selecting the right film, which is sensitive to match the colour temperature of the light used (Tungsten film for incandecsent light bulbs, daylight film for daylight).
On digital cameras we use the White Balance setting. Set it to “Tungsten”, “Fluorescent”, and so on. Or we can set it ourselves, and that is today’s tip of the day.
On many cameras you have a “K” setting. You can now adjust the white balance by setting it to the colour temperature of the light used:
- Blue sky: 10,000K
- Shade from blue sky: 7,500K
- Daylight shade: 6,600K
- Summer daylight: 5,500K
- Flash: 5,500K
- Mid afternoon daylight: 4,500
- Evening sunlight: 3,500K
- Tungsten light: 3,200K
- Sunset 2,500K
- Candle light: 1,600K
So setting those white balances makes light look white. Is that what you want? Then set that white balance to match the light. That is the simple method: to get white to look white, select the colour temperature of the light illuminating your subject. And by using the Kelvin scale, you can make this pretty exact. So if a light is too red for you, adjust K until you are happy.
But there is another method: If you do not want white, then set the white balance to a different value from the value of the light hitting your subject. I.e. you can shift white balance. So if I set my white balance to 5,500 on a sunset evening, I get not white, but red – which presumably is exactly what I want for a sunset.
Yes, you can do this on your computer if you shoot RAW, but I still recommend getting it right in camera.
And that was today’s tip!