There are a lot of ways to convert digital color images to black and white. One of the simplest it to choose HUE - SATURATION in your image editing software and simply drag the saturation slider down to zero. This is quick and
simple but provides very little control. I prefer CHANNEL MIXER.
Before I do the conversion, I want
to get an idea how the original image looks as a black and white in the three color channels: red, green, and blue. Choose the CHANNELS tab in your software and click on each channel to see how it looks.