This exercise provided a useful opportunity to practice:
Using the channel mixer
Converting colours into tones
Working with Hue and Saturation range of tools
It helped me to develop a greater awareness of how each colour react to my adjustments and the unexpected changes and side effects that these colour and tonal adjustments might cause.
For this exercise I selected two raw images that have strong contrasting colours. I used Adobe Photoshop/ Camera Raw to make adjustments.
Image 1 has a number of contrasting colours: the two dominating colours are magenta and cyan / blue; there are also green blue, orange and yellow.
I focused on the adjustments to Blue and Yellow colours.
I first saved the original image as a black and white (grayscale) version.
Image 1 Default black and white (grayscale) image in Camera Raw
I then adjusted the Blue and Yellow sliders in opposite directions as shown below.
Image 1: Adjustments Blue +; Yellow -
Observing the effect of this adjustment, I noticed that because the main object (the boat) is Cyan / Blue, raising Blue make the entire image look lighter. The boat that dominates the image appears to be almost white; the water reflections and the second boat in the background also appear light and luminous. These lighter objects seem to draw the attention away from the buoy at the foreground. There are also some changes to other colours that I did not anticipate, for example, the green and the orange colours appear to be darker.
Image 1: Adjustments Blue -; Yellow +
When I reversed the adjustments (Blue -; Yellow +), the boat became very dark (almost black), and the reflections on the water are also darker and so are harder to distinguish. The green, yellow and orange colours assumed much lighter tones; in fact the green seaweed is hard to tell apart from the sand.
Similar observations were made whilst making adjustments to the second image. This image has a mixture of green blue, red and orange colours.
Image 2: Default colour image in Camera Raw
Image 2: Default black and white (grayscale) image in Camera Raw
After the image was converted black and white, it was clear that the greens and the reds (contrasting colours) assumed similar tones.
Moving the Green(-) and Red (+) sliders in opposite directions made the Red colour brigth white and made the Green colour darker. When the adjustments are reversed, the Red box assumes a deep black tone and the Green cover becomes much lighter.
The image displays strong yellow and orange colour cast. The likely cause of this colour cast is the combination of daylight and strong artificial light sources in the Cathedral.
I noted that the colour of the stone walls and colonnades of the Cathedral can be used as a mid-tone reference point for adjustments: although it might not be purely neutral grey, it’s still near the middle of the spectrum.
