If you have ever worked as an extra in the film industry you will know how the work with colour in crowds. For example dressing the whole crow in varied shades of blue. The image naturally seems more harmonious. Sometimes I will go to weddings where the bride has chosen shades of pink and then every time I try to shoot the crowd two or three people will be wearing, rusty orange, yoke yellow or brown. So then, you can’t see the bride. When you look at the image you just see the people who are the contrast. By asking your guest to wear shade of a colour which compliments your choice of colours you will really improve your images.