Now all you need to do is make any other alterations and adjustments to the image that you feel are necessary to achieve your desired result. In practice I have found that either the Lab mode or Channels have given me the most pleasing results but different methods do work better on different images. Unfortunately there is no hard and fast golden rule that can be applied, but if there were that would take away all the fun
Below are my results from the same image using each of the methods shown above and tweaked to the best of my ability to show the best possible output.
Desaturate
Lab Colour
Channel
RGB to Greyscale Action and Channel Mixer
As both these methods rely on the Channel Mixer to do the work, the output is identical providing the same settings are used.
