Procedure: Take two photos that can be processed with 1. high or low key treatment and 2. a strong increase in contrast (and possible clipping in the shadow areas). In addition I added in a Low key image.
Workflow: I have been shooting with black and white in mind recently, and have chosen two photos for this exercise. The first was taken at my 'selection of infinite views' location, and is a wide angle view looking up at a lamppost. It needed severe correction of vertical in Photoshop which I did after I had done the treatment for high key black and white and high key colour. The colour version is quite washed out, which could be appealing in the right situation.
Image 1: Black and White High key treatment
My second image was taken at a favourite location, near the Museum in the city of Brisbane. I have chosen a very wide angle of view and captured some shadows in the foreground which lead the eye towards the 'louvre-esqe' pyramid and the dramatic sky beyond. I have dramatised the colours through selective processing of the colours (darkening the blue sky for example). I have pushed this image quite a bit. The colour image is very dramatic and colourful also, but does look a little surreal with the brightness and intensity of the colours.
Image 2: Black and White Contrasty treatment
In addition I have considered an example Low Key treatment. This image is shot up looking through a tree towards the sun shaded by some dark clouds. I have pushed the S curve down to deepen some parts of the image towards black and this has given a very dark moody image. The matching Colour image is quite similar, and the colours are only very subtle, so in this case it is quite convincing also.
Image 3: Black and White Low Key treatment
Conclusions: I am getting used to the idea of treating colours as tools in the conversion of black and white. Being able to selectively darken the sky in the second image without creating complex masks of the sky and not clouds is very powerful. It lends a very dramatic feel to the image.