Thursday, 8 July 2010

Digital Photographic Practice 1: Exercise 13: Managing Colour

For this exercise I chose three photographs from my family holidays, all with pronounced colour casts where the auto white balance has not achieved a fully satisfactory result. Here they are at default settings:

The boat photo has a distinct blue cast from the overcast lighting, the portrait of me (taken by make daughter) has some interesting mixed lighting which makes me look rather too tanned, and the doorway was lit by sunlight reflected from the yellow painted walls to give a very distinct yellow cast.
I am in the process of switching RAW developer from Olympus Studio – which is beginning to feel a little limited in the context of this course – to Lightroom 3. So the next three were all corrected using Lightroom before conversion to jpegs.

Even at these sizes there are some clear changes – I hesitate to use the word improvement because that’s a personal thing – although I think these are better.
For the boat I used the eyedropper tool on the superstructure behind the mast. This was a known gray - a white area in shadow. the end result was a change of colour temperature from 5100K to 5650K – which removes the blue cast neatly.
There is no obvious gray in the portrait. the shirt is in a variety of artificial lights, so using the eyedropper did not work. Instead I manually raised the colour temperature about 100Kand added a tint of +53 and increased the luminance of the blue channel a little to give a better skin tone at the expense of colours in the white shirt.
The Olympus E-1, which I used for this shot has an external colour sensor, which in this case was fooled by the light falling on the camera to give a near daylight colour temperature of 4850K. In this case the eyedropper tool used on the floor tiles reduced the temperature to 2950K and I manually tweaked the tint from the +5 recommended to –9 to warm the shot up slightly.
Finally I produced corrected versions iof the default jpegs n Photoshop Elements 2 (which has rather limited control) as follows:

The boat was corrected using the mid-grey eyedropper in the Levels window and appears very similar – if a little brighter – to the RAW conversion.The portrait was corrected using the colour channels in Levels (0.86 on the red slider; 1.13 on the blue) to give a result with reasonable skin tones but somewhat less green in the shirt – which is slightly more accurate. I could not make a good correction using the Levels box in the case of the doorway – so I resorted to the Colour Cast tool and then destaurated the yellow in the Hue/Saturation box.
As in the previous exercise, all these outputs (with the possible exception of the default setting on the doorway) are perfectly valid, and particularly with the more subtle differences, a matter of personal taste. It is also worth noting that although Lightroom offers significantly more options, perfectly reasonable results were obtained with relatively simple software.

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