Dear steemian!
Silhouette is the resulting effect in photography because of the significant difference between the reflection of the light of the main object on the front of the image against the background.
Usually the image of the object is just a shadow. To produce a silhouette, the light from the back of the object must be very bright then captured by adjusting the background light.
Silhouettes can also be produced by blocking the reflection of the main object's light selectively.
Thanks for attention
Regards