The above photo is my Iceland favourite - the colour version made it to the website's homepage banner as well as the wall of my apartment (on a large canvas print). The black and white conversion was an after-thought, as part of an experiment to take colour out of my favourite images and see the impact they have without this key component. Although the colour version remains a favourite, I was extremely happy with how this one turned out.
I rarely go out with the intent of creating a black and white image but below is one of those unique cases. I've shot this exact angle before and while playing around with it in Photoshop found the grayscale version was much more compelling. But I felt like getting the same shot in the early morning hours (with the tower lighting still on) would create a more impactful image. Not to mention I wasn't entirely happy with how I exposed the original shot. So that morning, although I was still shooting in colour, I had the final black and white rendition in mind while setting up the exposure. I'll never shoot in a B&W camera setting though; it's always good to capture all the original information to maintain full creative control in post-processing, ultimately achieving the ideal colour (shade) balance.
The next photo is another story altogether. The original colour version of this image of the DC-3 airplane wreckage on Iceland's black sand beach looks pretty much identical to the B&W one below; the "colour" of the sand was indeed black, the aircraft was unpainted so the remains of its metal structure had this exact worn out aluminum tone, and the weather above was exactly as you see it appears in this frame - various shades of gray with lighter highlights between the heavier clouds. The removal of colour hardly transformed this image but rather it added emphasis to the already gloomy and catastrophic scene.
(The entire crew of this US Navy aircraft survived the crash landing by the way).
The concept of "less is more" could be applied to many aspects of photography but this one (losing the colour) is about the simplest of its uses. Quite often with colossal impact. I've run into images, among others' and my own, where the "distraction" of colour takes away emphasis from what really makes the image the eloquent creation that it is. In less extreme cases, it could just be the final little touch that the image needs to "glow".