My second image (Jpeg format) was taken in Truro Cathedral.
Picture 1 Original Jpeg image in Adobe Lightroom
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.
Correcting colour cast using Levels
I started by adjusting the Levels (Image- Adjustments – Levels) in Adobe Photoshop. I selected the grey point tool and sampled different areas of the image to set mid tones. I did not find the adjustments satisfactory as the colours were becoming too strong and unnatural.
Picture 2: Colour corrections using Levels
Correcting colour cast using Curve
I then tried using the Click and Drag Hand (Curve Tool) to adjust the curve. I found that although the colours of the entire image were shifting to become lighter or darker depending on the direction of its movement, the yellow colour cast did not disappear completely. I’ve stopped when I reached the point whereby removing more of the perceived colour cast would shift all other colours and would make the entire image look unnatural.
Picture 3: Colour correction using Curve
I then tried another method and made adjustments in individual colour channels (Red, Blue and Green) in Curves. I made the final adjustments in RGB colour channel (see image below). I found this type of colour correction helpful and quite intuitive.
Picture 4: Colour corrections using individual channels (Curve tool)
I decided to experiment further in Adobe Lightroom: I opened the original Jpeg file and made adjustments to the Hue and White balance settings. The outcome of my efforts is below. It demonstrates that it’s very easy to introduce additional colour misbalance to an image.
It was interesting to experiment with different tools available in Adobe suite, including the Variations interface.
Picture 5: Colour correction using the Variations tool
Picture 6: Colour correction using Hue tool in Adobe Lightroom
Picture 7: A black and white version of the image (toned)
