When making the b/w images...
The world is full of the colours produced by the light. The colours are all about the light. As you know, there are light ranges we can't perceive. We only see what we can see. We capture the images with the recognigable lights unless we use special tools such as infared filters. Then what about the b/w images? They're kind of old fashioned but many photographers love to make them. Ironically, people, who live in this colourful world, love the black and white images very much. In my opinion, producing the b/w images is much harder than retouching the colour images. The reason why I decide to convert colour images to b/w images is very simple. I choose b/w images when the images don't have much impacts of the colour. However, even though my decision making is easy, the b/w process is not that easy to me. I'm still struggling to get the better results on b/w images.
If you're interested in B/W images, READ The article, 'Great Black-n-White Photos From Colour Film', writen by Darwin Wiggett. It's very helpful to understand about B/W conversion.