Exercise: Colour cast and white balance
Objective: To demonstrate the effect of differing light conditions on the overall colour of an image.
These four images were taken in cloudy conditions using the various daylight settings available on my camera:
3001 WB: Auto
3002 WB Sunlight
3003 WB Cloud
3004 WB Shade
Notes: It can be seen that the Auto and the Cloudy settings have produced very similar images although the Auto setting has produced a cooler (bluer) image. I think the Cloudy setting has resulted in a more pleasing, warmer image. The Sunlight setting has resulted in a cool image and the Shade setting, an image which is too yellow.
These next four images were taken in sunny conditions using the same daylight settings available on my camera:
3009 WB Shade
3010 WB Auto
3011 WB Cloudy
3012 WB Direct Sunlight
Notes: These results were as expected. The shade setting produced a result that was very warm, the Auto setting is acceptable but a little too warm for my preference. The cloudy setting was a less warm than the Auto and seems fairly acceptable. The Direct Sunlight setting gave a result that seems acceptable to me, some my consider it a little blue but I like that. It reminds me of Fujicolor transparency film.
The final part of the exercise (outdoors) involved taking pictures using similar settings in open shade.
Notes: Open shade seems to be the most problematic of the scenes for the Auto setting to measure. This is probably because of the variation in the colour of the light. i.e. Shade under a blue sky will look different to shade where the light is filtered by green leaves giving a green cast. The Shade setting seems to have coped pretty well though although I think the most realistic seems to be the Cloudy setting which is less yellow than the Shade.
The final part of this exercise involves a mixed (daylight and artificial) lighting source. Although the brief mentioned tungsten sources, I no longer have such lamps although the continuous spectrum lamps I have at home, do mimic tungsten fairly closely. Again the same scene has been photographed using the Auto, Daylight and Tungsten (incandescent) white balance setting on my camera.
This setting has rendered the scene outside the window naturally but the light inside is very yellow. Where daylight is is reflected from the sofa and table it is again natural looking.
Here the light from the lamps is looking more natural but the daylight has a distinct blue cast.
This is a compromise, the incandescent light is a bit too yellow and there is still too much blue in the daylight.
Conclusion: This exercise was worthwhile repeating (its very similar to one one in the Art of Photography) as it has re-familiarised me with the camera settings I need to be aware of when predicting the outcome of taking photographs in differing lighting situations.