Lets talk about Value
Value is one of the seven elements of art, it applies to colour &  black-and-white
images. It's all about how light or dark it is.

Image makers use value to create the illusion of three-dimensional form using a range of hues from light to Dark. "It creates various effects like highlights and shading, which provide more depth and three-dimensionality to artworks like paintings or drawings."(Meyer,E.2022). 

The number of colours or tones between your lightest and darkest colour determines the contrast of your image. Different values are created when we lighten a hue by adding white to it or darkening it by adding black.(KQED, 2020, 12:01). High-contrast images incorporate a large number of tones between your lightest and Darkest colours. Low-contrast images do the opposite.

Image makers use value to achieve a wide range of outcomes. Pairing light and dark elements can draw the viewer's eyes to a particular area of the image. While areas with similar tonal values recede to the background. This is just one example of what can be achieved when you understand value.
Dive deeper
https://artincontext.org/value-in-art/
https://www.widewalls.ch/magazine/value-in-art
https://yourartpath.com/what-is-value-in-art
References

- Mayer, E. (2022) ‘Value in Art - Understanding Value as an Element of Art’, Art in Context, 1
August. Available at: https://artincontext.org/value-in-art/ (Accessed: 22 September 2023).
-KQED (2015) Elements of Art | Value 5 January. Available at: https://www.youtube.com/watch?v=AAwYHNo31ZQ&list=PLiOil1qP-cMURN_8baOr3QWfySmIjqKIj&index=5&ab_channel=KQEDArtSchool (Accessed: 22 September 2023).