One of the most important factors in the decision to add black and white to your clips is whether or not the video itself can handle this kind of alteration. Color film can maintain less light at times and often helps people make out the images with greater clarity. Black and white, or desaturation, can cause this to become less clear and therefore make viewing the image laborious. Add the filters to the clips and see if they work out, and take special attention to light, contrast, and motion over the background.