Lights have importance because we see objects clearly in them. Shades add a touch of beauty to the object which we photograph. When there is an interplay of both of these a fine photo comes to existence. All good photographers take into consideration the overall beauty and impact that is caused by mixing both of them. It is particularly nice at the time of sunrise as well as sunset. Shadow is also a fine subject and if we know how well to present it it gives a fine view. Long shadows are particularly interesting and they happen when sun us setting. The ling lines are simply beautiful and attractive. See the bicycle photo by me.