Let's talk about contrast
Black and White, Thick and Thin, Bold and Understated. These are all examples of contrast.
Contrast is one of the 12 elements of design. 

When you place two things that are vastly different from each other together you create contrast.
The difference has to be very obvious but not too obvious. You still want your viewer to feel the satisfaction of connecting the dots for themselves.

Why use contrast in your image? Because it is exciting! I never get tired of seeing two different
elements live in a composition harmoniously. It gives me hope that the world can be the same.

Video by Sauer's Virtual Art Room | Principle of Art: Contrast

List of references
Sauer's Virtual Art Room. Principle of Art: Contrast. [online] Available at: https://youtu.be/xKCPWjTQWrY?si=a8TYYYkYPAEaUaEn [Accessed 28 Sep. 2023].

Deepak John Mathew (2011). _Principles of Design Through Photography_. SCB Distributors.