- Taken from Wikipedia.
Colour balance is extremely important within the photo taking practice and has many influential factors that can affect it. The main factor to be considered is light source. Different light sources have different colour temperatures which generate different coloured lights for example tungsten lighting produces a yellow light, fluro's can come in many different colours and speed lights are generally blue. The higher the k number the cooler the light source is.
Colour balance needs to be adjusted in order to render a correct colour temperature within in an image, almost counteracting the light source so the image produces accurate colour.
The help of additional filters and gels can assist in this process.
We went to the Canberra Convention Centre and took an abundance of photos in different light sources, daylight, fluro, tungsten and mixtures of the three in order to make custom white balances on our cameras. Apparently this is something we should be doing, using a grey or white card whenever we shoot, which to be honest I had never done properly before. But now I know how to do it.
My images have since been lost as my housemate borrow my SD card and formatted it. However I can display pictures from within my group (Taken exactly the way I had anyway) You can see those images courtesy of Sarah Lanham on her blog here: http://sarahlanhamtechwork3location.blogspot.com/
I don't know how beneficial using an expo disc would be EVERY time you had a shoot.
Using a grey card isn't as complex and time consuimg as the expo disc. I think it's important to produce colour correct images and using custom white balance is a guaranteed way of producing these; if you do it properly.