Understanding Tonal Range in Photography & Why It’s Essential For Creating Exceptional Photos
Tonal range is one of those fundamental basics of digital photography that is often overlooked or misunderstood… let's face it… it's not a sexy topic!
Whether you're a hobbyist or pro, we are all guilty of skipping the basic building blocks of photography at some point. Light and it's luminance values in particular.
Light is the most essential element for any image. Without it, it's like shooting with the lens cap on. Master light, and you'll be able to shape your subject to tell a story, add depth, increase interest, and make your friends, family, and clients say "WOW!"
Tonal range is an ingredient of light. If you wish to create exceptional photos, then understanding the tonal range will help you master light.
Table of Contents
What Is Tonal Range In Photography?
The tonal range in photography is the range of tones between the darkest and brightest areas of an image that are captured by your camera.
The darkest area represents pure black, and the brightest is pure white. In-between includes the shadows, mid-tones, and highlights.
Tonal range in photography is the brightness levels of light captured by your camera. This can range from pure blacks to pure white and shades of grey in-between.
An image with a wide range of tones will have pure black to pure white in your image.
A small or narrow range of tones will include a smaller range from shadows to highlights, no pure white, or no pure black, or neither black or whites.
The brightness levels within your photo
also determines the extent of contrast.
If you capture an image with a small range of tones, the overall contrast will be flatter vs. a larger range.
In post-processing, you can increase the range of tones to add more contrast by stretching the image to the outer edges… by adding pure black and pure white.
In photography, the tonal range is divided into 5 luminance (brightness) values; black, shadows, mid-tones, highlights, and whites. Let's review each with a photo example.
Pure black in an image is a result of zero luminance. It's void of any detail.
There will be times when a photo looks like it is dominated by pure black (image below). However, a closer look at the pixel values will reveal that some of them are a lighter shade of pure black. Check out the image below.
The image below includes a blue overlay mask that shows where pure black is in the photo.
Some areas around it also appear to be pure black due to the brightness levels. However, those areas contain small amounts of detail and those pixels reside within the “Blacks” zone.
Pro Tip: Your histogram is a good source of finding detail in areas that appear to be pure black or pure white. With this knowledge, you can edit the image accordingly to make it visible.
Pure white also lacks any detail and this is referred to as the White Point (right side of the Histogram).
The image above shows the White Points in red (mask overlay)
Shadows consist of luminance values that are brighter than the blacks. Sometimes, shadows can appear to be closer to black.
But, by reading the histogram, you'll realize there's more detail than meets the eye!
At the same time, if you over-edit your image, you can push the shadows to pure black and lose texture in the process.
Use those clipping masks in Adobe Camera Raw and or Lightroom to avoid over-editing!
Not too bright and not too dark. That, in a nutshell, is the mid-tones of your image. Midtones are an essential part of any image. However, if only the mid-tones are captured, it results in flat contrast.
Highlights, the opposite of shadows… much brighter. Like with Shadows, your histogram can tell you if there's more detail in this range.
The tonal values in the Whites are the opposite of Black tones. Pure white or 100% luminance has no detail or texture in it. The White zone consists of darker shades of white compared to pure white.
If your highlights are "blown out," then you'll have pure white in those areas. Over editing can cause details to be lost due to shifting the highlights too far.
To have or not to have pure black and pure white in your image? That is the question!
The answer depends on who you ask. Some photographers insist that photos should always have a pure black and white point. This way, the image will have the full tonal range of light captured. Others will disagree.
Who is right? Both! Actually neither! So, which is it?
It doesn't matter what other people think.
What do you think? What do you like? What story are you trying to tell?
All that matters is your personal preference and the creative vision you have for that particular image.
Limitations In Our Digital World
All digital cameras have a similar flaw in the inability to capture the full brightness levels of a scene. The darkest point to the brightest point might be too much for your sensor to capture all the details.
Dynamic range is another digital phrase you need to know. It's often confused with tonal range. But they are entirely different!
Dynamic range refers to the maximum and minimum brightness levels of a scene. In other words, from the darkest areas (shadows) to the brightest areas (highlights). In nature, the dynamic range is infinite.
Your digital camera does NOT have an infinite dynamic range. Neither do your eyes! This means your camera and your eyes can not see all the detail in the
shadows and highlights if the brightness levels are outside of that range.
What does this have to do with photography?
If your camera is limited in its ability to capture the full dynamic range then you will not be able to capture all the detail in the shadows and or highlights.
Dynamic Range Solution
Understanding the dynamic range is beyond the scope of this article. Which is why I recommend studying what dynamic range is next.
Ever have "banding" in your image? The most common occurrences of banding are seen in skies and backgrounds of a solid color.
Banding occurs when there aren't enough tones to create a seamless transition from one color to another. You can visibly see this since the shade of one color ends abruptly and is followed by a new color… creating a stair-step effect. This is often caused because your digital file doesn't contain enough colors (tonal range) to smooth the transition.
For example, an 8-bit file consists of 16.8 million possible colors. A 16-bit file, on the other hand, has up to 281 trillion colors! More colors equal a smoother transition from one color range to another. Trillions of colors will also reduce the chance of banding during editing.
The solution is to use a higher bit depth. If you shoot in JPEG, then you're limited to 8 bits since nothing higher is supported. On the other hand, Raw shooters can record anywhere from 8 - 16 bits, depending on your camera, of course.
My Nikon Z6 offers two-bit depths for Raw recording, 12, and 14 bit. For my photos, I've chosen a higher bit depth.
The downside is the file is about 30% larger vs. 12 bit. It's a trade-off I believe is worth it since I'm able to capture trillions more colors and banding is practically non-existent.
You'll also notice that if you shoot in 12 or 14 bit, for example, and open the raw file in Adobe Camera Raw, it will be converted to 16 bit! That is if you set up preferences to switch to 16 bit.
Now that you know what the tonal range in photography is and it's limitations, you'll be able to create exceptional photos. This can be achieved by capturing the full range of tones at the time of capture. Or if need be, by fixing it in post-production.
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