Many people like to use their onboard B&W conversion when shooting with their cameras. Or simply use the Desaturate function in Photoshop (PS). Here’s a quick and dirty method that will give you more flexibility for converting colour photographs into B&W. Note there are 1001 ways to do the conversion but I like using the Channel Mixer.

The Channel Mixer is a relatively powerful tool. It can be accessed in PS by these menus - Image > Adjustments > Channel Mixer. I actually use this in the Layers mode but that is another discussion for another day. Once you understand this concept, you can easily apply it to any photo for conversion.

Here’s the original photo…

Now, click on Monochrome and pull the Red channel to 100% (leaving the other two channels as zero)

If you select 100% of Green…

And Blue 100%

Achieving the desired result requires you to mix and match the percentages of Red, Green and Blue channels and they do not necessarily have to add up to 100% (you can go beyond). Here’s what I chose for this. There are specific guidelines as to how your black and white photos should look like but they are only guidelines not gospel.

Final Result Red 80%, Blue 20%

Compare it with the simple Desaturate function…

You will see that the Channel Mixer method yields more details and contrast in the clouds and the reflections especially.

Good luck!