We were set a task to choose an image to use in Photoshop and experiment with different controls which gave the scene a different look and feel. The controls used were: Black and white, hue/saturation, desaturate and channel mixer. I chose a photograph of a sunset that I had taken on holiday prior to starting the course, using a Nikon Coolpix compact camera. It is not a manual camera and so I am unable to quote any settings.
First changing the image to black and white then using the channel mixer: I increased red to +105, green to +17, and turned the blues down to -33%
Here I changed the hues. The controls are on slider scales that you move up and down and as you do you immediately see the effect it has on the image