In the dim, dark old days of film whenever we encountered a situation like the one on the left we were put in a bit of a pickle.
Film is designed to be shot during the middle of a sunny day. Whenever you shoot film under different light you end up with a colour shift.
When you noticed that colour shift the most was when you photographed under artificial light - house light bulbs, fluorescent lights, big strong halogen floodlights. I'm sure you've all seen the results which vary from a bright orange glow to a horrible yucky green colour.
We had a couple of choices - we could either live with the funky colours or put lots of coloured gels in front of our camera to try and get a more natural look. The gels were often a pretty hit-and-miss affair because not all lights are the same light temperature so you might get a great result one day and a pretty ordinary one the next.
Digital has pretty much solved the dilemma with the White Balance button. Shooting in your house with the lights on at night and not using a flash? Put it on the Tungsten setting (a little lightbulb). Shooting under flourescent lights? Put it on the fluro setting. Hell they've even got a setting for cloudy days and when you're in the shade. Or to be even quicker you can just stick the camera on Auto and let it do its thing.
The question is do you want to? Sometimes you may but in the end photography is an art form and you have to make an artistic decision. The image above was shot at the Tsukiji Fish Market in Tokyo. I had to get up at about 3am to make the 5am giant tuna auctions. The place was lit up by giant halogen type lights on the roof. Filtering them with a blue gel on the lens brought all the colours back to normal and the pictures looked, well, normal.
But when I left the filter off and just let the film do its thing I got this lovely orange colour. It certainly wasn't quite how it appeared to my eye but it is a much better representation of what it felt like to be there. This is one of my all-time favourite pictures and I don't think it would have been anywhere near as nice if I'd filtered the light properly.
So before you go sticking your camera on Auto White Balance have a play with the settings. I leave mine on Daylight setting permanently now because I know I'll get the same look as I did with film. For tricky lighting situations where you're not sure how you want the image to look shoot RAW and that way you can process it to your heart's desire when you get home.