Recently I created a series of images called "Shadow People". Originally an experiment with tonal mapping in the development process, I found the maps themselves fascinating and they grew into the series that you’ll see at the end of this essay.
But before going there, I want to pause on something fundamental: how we perceive depth in an image.
Layers of Distance
Look at a range of mountains. Even when they share the same color and texture, we instinctively know which are closer and which are farther away. Why?
Because of tonal differences, their relative lightness or darkness. Near objects appear darker and sharper, while distant ones fade - lighter, hazier, and often bluer. This effect is called atmospheric perspective.
Artists have known and applied this for centuries. Leonardo da Vinci was the first to describe atmospheric perspective in writing, noting how particles in the air - dust, vapor, and especially those that scatter blue light - make distant scenes look softer and cooler. The farther away something is, the more air and particles sit between us and our object. That’s why distant mountains look hazy and fade to blue. It’s not just poetic - it’s physics.
Turning Concept into Technique
Painters can use the principle of atmospheric perspective to create depth without changing a single color. By adjusting tonal values - the lightness or darkness of a tone - they can push objects back or pull them forward. Just making the foreground darker and the background lighter can be enough to trick the eye into seeing depth. Famous landscape painters, J. M. W. Turner comes to mind, who masterfully employed this technique.
Photographers face a different challenge. We don't have a blank canvas and the world doesn’t arrange itself neatly for us. We have to shape depth by dodging and burning - lightening or darkening selected areas. This technique is as old as photography itself and is applied during the development process. And whether you work analog or digital, the amount of work remains the same. Ansel Adams famously spent more than a hundred hours on a single print, carefully adjusting tones to guide the eye.
It is okay to dodge and burn rather intuitively and not to follow strict rules - liberties of an artist. But in this experiment I wanted to see what a more technical and systematic approach would render. So I organized the tonal values of my images, mapping them front to back. I assigned the darkest tones to the foreground, the lightest to the background, and adjusted everything in between. Algorithms can help with this mapping, but they’re far from perfect - manual refinement is always needed.
What the Eye Sees
Compare two versions of the same street image: one in simple grayscale, the other mapped by tonal depth. The grayscale version feels busy and scattered, while the tonal map organizes the scene and gives your brain a clearer path.
Here is another set:
An image with lots of detail that takes time for your brain to "read". Even though this particular image has a natural leading line to guide, the tonal map helps to organize the elements.
After bringing the colors back in, and therefore adding more information for your brain to process, the tone-mapped image on the right is still easier to read. Although the changes are just subtle, your brain notices. Long before you consciously analyze an image, your eyes and mind are already processing depth cues and prioritizing what feels clearer.
The Role of Color
Of course, color still matters. Warm hues like red, orange, and yellow feel closer and more inviting because of our evolutionary ties to fire, sunlight, and warmth. Cooler tones - greens and blues - tend to recede. But while color influences perception, tonal value almost always has the stronger effect.
A Final Note
This experiment taught me to see depth differently. Next time you look at a painting or a photograph, take a moment to ask: What makes this image feel deep? Which tonal choices guide my eye?
You might discover that your brain has been doing the work for you all along.
I hope you found this topic interesting and inspiring. If you want to see more of my work, check out my website and follow me on Instagram. Previous issues of my blog can be found here.
Shadow People - Imagery down to pure shape and tone—ghosts of their former selves. The protagonists fade into shadows, lost in monochrome. It’s abstraction as invitation: with the details gone, the story becomes yours to imagine.
Please feel free to share this blog with anyone who might be interested. I always welcome new subscribers.
Credits:
Hilda Champion