Saturday, April 23, 2005


The shot originally had a blue cast because of the white balance mode I had set (tungston). The floweres are also actually white. I used the Gimp's Sobel edge detect filter to get the high contrast and bumped up the saturation as well. It can be seen that by far the dominant colours are cyan, blue, and yellow, more or less in that order. The picture was taken at about 5:15 am on the 23rd of April (yesterday barely) on my way to the bus stop. I'm in general using the dark lighting conditions to experiment with shutter speed.

I think the colours worked out the way they did because of the adjustments to colours that are made under the tungsten white balance mode for the camera. Since the camera workes with reflective light it deals in the subtractive colour model. Tungsten lighting is yellowish. To bring a photo back to a neutral white baseline you need to subtract yellow from its colours. This makes greens go to blue and yellows diminish (I think). Taking a photo with no ambient light and the assumptions of tungsten lighting results in a skewed-colour image.