Knowing your tonal range is one of the most fundamental skills that can get you closer to understanding how your digital photography strikes the viewer at first glance. The range of tones in your image affects its mood and feel to a huge extent, but it can sometimes be difficult to define or quantify.
That’s exactly what today’s guide is here to resolve. Let me walk you through the basics of tonal range in photography so that you can use it to improve the quality of your work!
What is Tonal Range?
The tonal range is one of those keywords that often get confused and misidentified in photography circles. To give you the most straightforward possible dictionary definition, tonal range describes the gamut between the darkest and lightest tones of light values that your camera can capture. This range of tones encompasses gray tones, blacks, whites, and anything in between!
In mainstream digital photography, the full range of tones is usually subdivided into a few tonal areas. Let’s look at each of these to see how their presence or absence affects the look of your photos!
At the top end of the tonal range, you’ll find the whites.
This includes pure white, which is a luminance value of 100% with absolutely no details or texture. On a histogram, pure white exists as the absolute white point on the far right edge of the graph.
Other whites with lower luminance values also exist in this realm and can often be tricky to tell apart from the naked eye. Thankfully, the histogram can easily tell you exactly what light values you are looking at, so it is indispensable when analyzing tightly grouped bright areas!
Within the white zone, you also have your highlights. Highlights are the opposite of shadows in the sense that they are localized areas of high luminance, just like shadows are layers of low luminance (i.e. less lighting).
In situations where your camera’s dynamic range is hitting its limits, you may face so-called blown-out highlights. This is a case where highlights are exaggerated and may actually reach close to pure white. This can cause a loss of detail, especially in badly overexposed pictures.
Your mid tones are just that: the middle ground of your tonal values. Not especially light nor fitting in with the darker areas, mid-tones are a necessary and healthy ingredient to any good photo. Just be aware that an overemphasis on mid-tones can lead to mushy-looking, drab images with low contrast!
Blacks and Shadow Areas
Blacks, as you could probably surmise, are the mirror image of whites. Forming the bulk of the dark areas within your photography, they play the important role of balancing out high brightness levels and developing more detail and contrast in your images.
Just like whites, blacks can be absolute, with a zero luminance value and lacking any and all texture. This is represented by the far left extreme of the histogram.
Shadows, meanwhile, form the moderate range of tones within the dark spectrum, being the aesthetic counterpart to the highlights. And just like highlights that may face blow-outs, shadows can also become excessively boosted, which results in pure black areas devoid of details.
The Difference Between Dynamic Range and Tonal Range
Letting the above definition of tonal range sink in, you might be hearing the ring of a familiar term: dynamic range. In truth, the two are closely related terms.
Nonetheless, it’s important to remember not to confuse the one with the other! Dynamic range and tonal range describe entirely separate, if related notions.
The former relates to the range of light values that your camera (or the human eye, for that matter) is capable of detecting. While dynamic range is a complex topic, most would agree that a higher dynamic range is preferable for just about any genre of photography, as it allows you to squeeze out and capture a high contrast image without great losses in detail.
Meanwhile, the tonal range is very much a relative term. The range of tones in one photo can be completely different from that of a different image, even if captured on the same day with the same gear. This is because tonal range only describes the real distribution of luminance values within your frame. As such, tonal range is something that forms based on your style, technique, and understanding of light and exposure.
That’s why having a solid grounding in tonal range can help you unlock the full potential of your camera and your creative vision!
The Quest Towards Full Tonal Range
Many photographers, especially those starting out, proclaim a dedication towards achieving ‘full tonal range’ wherever possible. This sounds reasonable enough – wouldn’t you rather have a bigger range of tones than a more restricted one?
However, the aim behind this principle can actually be quite misplaced. A full tonal range exists when every major group of tones – from pure black to pure white – is represented to some degree within your image.
This is not a rare thing, and indeed it can happen even without conscious intent or need for editing. Particularly when shooting outdoors in high contrast scenes that challenge your dynamic range, producing a full tonal range inadvertently is very much a possibility.
The question, then, is not ‘how’ but rather ‘why’.
Why is a Full Tonal Range Preferable or Advisable?
The answer: it may not be, after all! In truth, the extent of your tonal range is a matter of personal preference. There are a lot of photographers out there who go to great lengths to make sure that their images contain no pure black areas to preserve every bit of shadow detail they can get. Others will apply the same standard to the whites, too.
Meanwhile, others will see value in chasing full tonal range across the frame. The added contrast can lend both landscapes and portraits more visual ‘pop’, for instance, which some of you might prefer.
Managing Luminance Values in the Field and in the Studio
Now that you understand the basic principles behind tonal range and why it is so important, let’s look at how you can manage luminance values consciously and with predictable results.
As previously mentioned, one of the greatest aids that you can use for determining luminance in your scene is a histogram. If you’re using a modern mirrorless camera or DSLR, you may have the option to display a histogram within your viewfinder. This can be a post-exposure histogram that automatically appears after each shot. In the case of more advanced gear, a live histogram reflects your choice of camera settings and composition in real time.
Using the histogram, where blacks are on the left and whites are on the right edge of the graph, it is relatively simple to grab an overview of the tonal range and balance of your shot.
By focusing on peaks in certain luminance values and noting their position on the graph, you can see how your lighting conditions draw attention to or away from certain areas of your composition.
In the same vein, you can use a histogram to make tonal range adjustments much easier when editing your digital photography. By precisely editing the white point and black point of your images alone, you can greatly affect both the localized brightness levels as well as the level of detail and tone.
A Short Introduction to the Zone System
Pioneering and renowned landscape photographer Ansel Adams developed his own unique process for handling luminance values in his photography. Called the Zone System, Adams’ invention is still taught to countless student photographers to this day.
The basics work as follows. Imagine every possible luminance value as belonging to one of 11 ‘Zones’. Zone 0 is absolute black, void of detail. The darkest of the dark, in other words. Zone 10, meanwhile, is absolute white, the peak in brightness levels achievable in a photograph.
In between, you have a series of Zones, each pertaining to one particular level of luminance. Ansel Adams’ MO revolved around balancing out each of these Zones, taking great care to lend each of them sufficient ‘breathing room’ within the frame.
This makes Adams one of the principal proponents of the full tonal range principle. And with the kinds of photos that he managed to produce this way, it’s hard to fault his method!
No matter where you’re coming from with your photography, I think an excursion into the Zone System is worth a shot. With some practice, it can hold the key to giving you a richer, fuller understanding of how tonal range works to paint your pictures with light and dark.
How An Understanding of Tonal Range Can Improve Your Black and White Photography
Nowhere is a solid grasp of tonal range more crucial than in black and white photography. Ansel Adams devised his Zone System entirely with monochrome film in mind, after all!
Shooting in monochrome transforms all of your photography into a scale of tonal shades, from the brightest absolute white to the darkest areas in the shadows. An essential part of mastering black and white as a medium is understanding the way contrast and light play such a significant role.
This makes the proper command of your tonal range the difference between an expressive black-and-white masterwork and a so-so shot.
Especially in black and white photography, but definitely not exclusively, I recommend you shoot RAW. A RAW file contains all the uncompressed depth of luminance values your camera sensor can capture. This means that you can maximize your dynamic range and latitude in post processing, allowing you to play with tonal range much more easily and correct smaller mistakes.
Even if your regular output does not include a lot of monochrome shooting, I suggest making the switch as a useful tonal range exercise.
Mastering Tonal Range Through Experience
In the right hands, the tonal range can elevate digital photography to a higher level. Understanding how dark areas and light areas, along with the ever important mid tone, form the personality of your image is part and parcel of both professional and fine art photography.
I recommend you use the tools I outlined today – in particular, the histogram, RAW post-processing, and the Zone System – to practice and develop your own tonal range. Whether to emphasize maximum detail or to prioritize contrast is up to you, of course.
What really matters most is that you make a conscious effort to take tonal range into account when you’re out shooting. With time and practice, a deeper understanding of the underlying mechanics is sure to follow. Good luck, and have fun!