Black and white is really used for specific purposes, often to give the landscape or portrait a timeless feel, or to really stylise a picture that otherwise can lack dimension.
I don't use black and white frequently. I normally desaturate and add more contrast to my pictures or just leave the true colours in.
But as I was working on a selection of shots that I took during a recording session, i realised that I do use black and white when colours and their variety are too distracting and take away the actual content of the picture. For instance I shot with no flash since I had a video light on my hotshoe and I just took a few snapshots every now and again, I didn't want to switch from the video light to the flash. So the colour balance is less than perfect and I tend to look at that flaw more than I look at the actual picture. Turned into black and white and your eyes aren't distracted by the colours, their richness and clashes. You can only see the shapes, the range between light and shadow, and in this picture, the face and the scene. Also when talking about a series of pictures, if the colour balance is very varied from shots to shots because they were taken at different times / conditions, then black and white would be a quick fix option too, though it is sometimes worth spending an extra time neutralising all the pictures.
Here's another example of a picture that I'm not crazy about in colour, but when turned into black and white, the colour imbalance is removed and in a way it is about revealing the true nature of the picture, what it is about, just like when you shoot you remove so many elements of the reality in front of you to reveal just what matters to you at the moment.
Sometimes I am torn between the love for colours and the flawlessness that black and white bring to a picture. A while back I took a series of portraits of a Russian poet, Mary D. A brave woman who fought strong all her life and she asked me to take a flattering portrait for a funding application of some sorts .
One of the pictures that she chose was this one because we both loved her eyes, very innocently blue and lighting her whole face, and the touch of red from her top.
As you can see on the unworked picture on the top, there's also an awful lot of red cast and red on her cheeks that compete with the beauty of her eyes.
I had worked on that (quite brutally I think now that I have a second look) but despite the fact that I love the colours on the picture, I still think a contrasty black and white does her more justice and the colour one because suddently we just see the intensity of the eyes first.
