What is the zone system?
The zone system is a method for controlling tone in black and white photography. It comes from film photography and is especially suited to large format work. It enables the user to accurately visualise the tones of the finished print at the time of exposure. It relies on careful preparatory testing, repeatable technique, and use of a spot meter.
While I won’t be insisting on full testing here, I will assume that the reader is game for a little work, has some patience (you are doing large format photography!), owns a spot meter, and will be processing and printing his or her own film. While you can learn from doing parts of what follows, this really is a ‘system’, and needs to be embraced as a whole. I should also point out that the settings you will discover will only be good for you, for your equipment and technique. The zone system is nothing if not personal.
What are the zones?
In the analogue medium of film, there is the potential to record a vast array of tones. These tones are continuous, in the sense that they move seemingly indistinguishably from one to the next. This is a wonderful property of our analogue medium, but it does provide something of a hurdle when it comes to getting creative control.
This is where the zones come in, as they are a shorthand for describing and potentially altering the tones in our prints. We divide our images into a set of nine steps or zones of tone. They run from zone I which is nearly pure black all the way up to zone IX, which is effectively the white of our printing paper. Zone V is a key tone and is situated in the middle.
Metering, zone V, placement and fall
Let’s do our first exercise. There’s no need for your Intrepid just yet, a digital camera will do. You may wish to to cast your eye over this section because there is a strong chance you will be familiar with its concepts. Feel free to skip ahead if you are confident about these fundamentals of exposure. You will forgive me for covering them, because we simply can’t proceed without them.
Find an evenly lit and empty surface. I’m working in a room that has white walls and these would be fine, but any empty surface will do. Set your camera to manual mode and make an exposure following the camera’s light meter. You have just exposed the surface at zone V, which will look something like this:
Let’s say my exposure is 1/60 second at f8 and ISO 200. You are now going to make an exposure at one stop less. I could change my shutter speed to 1/125 second or I could alter my aperture to f11. The resulting exposure will be zone IV and will look like this:
We could expose for zones III, II and I by continuing to reduce by one stop at a time. Instead, let’s expose for one stop more than our original exposure to get zone VI:
I hope you are starting to get a feel for the zones at this point. We are making a simple meter reading of a surface which, because of the way that meters are calibrated, will always lead to a ‘mid-grey’, zone V exposure. We are placing our exposure on zone V. However, we’ve started to do something more interesting too, namely placing our exposures on other zones. We can move up and down the scale simply by altering our exposure in the appropriate way, a stop at a time. There is an elegance, I think, to the relationship between stops and zones. Try printing your digital zones and sticking them together side by side. This can make the relationships between the zones more evident.
We can now start to think about how this helps us to divide the broad areas of tones in an image into a more digestible set of tones. The zone system is a descriptive tool. Here is an exposure that I made in my studio:
A meter reading was taken from the white umbrella, which renders that as a zone V. Note though, that this isn’t the end of the story. While we have placed the umbrella on zone V, other objects fall on different zones. We have a zone III black softbox cover, a zone V table top and a zone VI foil softbox inner. ‘Fall’ is the sister concept of placement. When you place one tone - you only get one choice of aperture and shutter speed after all - other tones in the scene fall according to their own relative brightness. Let’s try to maintain our practical approach by showing what happens when I alter the placement of my umbrella surface:
A one stop increase in exposure for the umbrella results in visually ‘whiter’ surface. It is now on zone VI. Zone VII might be an even more appropriate choice. But notice the effect on the other tones which all move up by one stop. They are falling one stop up the scale too: I’ve got a zone IV black area, a zone VII foil inner and a zone VI table top. The less than satisfactory black softbox cover is a consequence of the new umbrella placement. This is ordinary exposure at work: I can’t eat my cake and have it too. The zone system will provide a way to get around this problem, as we will see shortly.
A little planning
We are now in a position to start our zone system work in earnest. Before we proceed, there are some decisions you will need to make. The reason for this is something I alluded to earlier: the zone system is only good for one person’s practice, which includes some specific decisions about media and printing method. My first question is, therefore, what film do you want to use? My recommendation is Ilford HP5 plus because it is compatible with a wide range of developers and is relatively affordable. You are certainly not limited to that film, but do ensure you have a developer you can source regularly and easily. I also need to ask you: how will you be printing? Will you be enlarging or contact printing? If you have printed on more than one paper, it is also time to settle on one for the time being.
Your own personal film speed
This first part of our zone system work has the potential to improve your photography considerably, even without following through the system in its full glory. I wrote above that all meters are calibrated to produce a zone V grey when a reading is taken from a plain surface. This is true, but needs to be qualified. Whilst theoretically your and my zone V should register the same on our negatives, variables like shutter speed calibration, developer temperature, development agitation technique and so on will introduce differences. More often than not, it is also true that the manufacturer’s recommended film speed leads to a somewhat dull zone V, together with shadows lacking detail and greyish highlights.
We’re going to address this problem by determining the best film speed for you. You first need to set up a scene in controlled lighting, that is rich in detailed shadows (zone III). Try to find a variety of textured surfaces that will render a variety of tones. Think about the direction of the light in the scene, i.e. ensure that it emphasises and enhances the textures.
You are now going to use your Intrepid to make an exposure at the manufacturer’s recommended film speed. In the case of HP5 plus, that is 400. If you have a spot meter, take your reading from a mid-grey surface. The best results here will be obtained if you can source a ‘Kodak Grey Card’ to take the reading from, but you can get close using substitutes. Alternatively, use an incident meter pointing at the camera.
It is sensible to work a few stops down from wide open on your lens. You may need to focus your camera first wide open, and then stop down when you are ready to expose. With my own Intrepid in the studio, I can nearly manage without the dark cloth when my 150 mm, f5.6 lens is wide open. Start with your camera’s back upright and level, and remember to tighten both front and rear standards as well as the focus when you are ready.
After the first exposure, make a second at ⅓ stop more. In my example, that would be at ISO 320, not 400. Do a third at another ⅓ stop (250 for my HP5). When increasing your exposure in this way, use aperture not shutter speed. Aperture is more reliable in such controlled conditions, especially on the older, second hand lenses we are likely to be using on our Intrepids. A label with the film speed used in the scene is a great idea to help you keep track of the exposures.
Now develop your film at 15% less than the manufacturer’s recommended time. Bear in mind that for future results to be consistent, you will need to re-use whichever development regime you use here, i.e. developer type, dilution, agitation method, temperature, and so on. Feel free to examine your film on the lightbox or a handy window now: you may be able to glean something significant in your results if you have some experience of reading negatives. Don’t print them yet, as there is another step that I have deliberately omitted. Here are some of my results:
These tests were quite a revelation for me, and show a clear advantage to using ISO 250 for HP5 plus in my work. The shadows are much more open, and the mid-grey much lighter and livelier. The effect we now see at work is the basis of the old advice to ‘expose for the shadows’. A first priority is to get the shadow areas right and then we can go on to fine tune the highlights.
In quest of paper-black density
Our next step usually precedes the one we have just taken. I held back, however, because it makes sense to look at film speed immediately after a discussion about the zones, placement and fall. Also, as the zone system can be intimidating, setting the reader off on the quest for paper-black density at the start may be self-defeating.
We could go ahead and print our negatives, but what time would we use? We could do the usual kinds of test strips and make a visual judgement. That is not systematic enough for the zone system, and it has a much more informative method. What we really need to know is a standard minimum printing time for our negatives that will produce the kind of black our paper is capable of producing. Once we’ve found such a time, we can print newly made negatives to a standard time. It will be variations in exposure and development we end up seeing as our work progresses, not variations in printing.
To start the test take an unexposed sheet of film at the size you are using (i.e. 4x5 or 8x10) and develop it as you did the previous sheets. Your enlarger should now be set up in the way that you will be using it when you print. For example, when I am contact printing 8x10, I use my enlarger at full height and fully de-focussed. I also use the same grade, grade 2 (it is a multigrade machine), and enlarger lens aperture (two or three stops down is a good start). It’s a good idea to record the settings, and I usually do this on the back of my test prints so they don’t get lost.
Make a test strip using your developed and unexposed film. The aim is to have steps running from distinctly grey through to black. It doesn’t matter what intervals of time you use, as long as they are not inconvenient and clearly show changes between the steps. As you are using sheet film, you will be able to leave at least half an inch between the sections.
What we need to discern are those two steps that no longer show any perceptible difference from one another, i.e. the point at which ‘black’ is reached, where extra exposure will no longer darken the paper. It is advisable to look at your strip in good but not bright light. The smaller of the two times becomes the standard time for printing your zone system negatives. The example below is a scan from a contact sheet and will therefore be imperfectly reproduced on this page. Nevertheless, it should hopefully show what such a test strip should look like. I settled on 27 seconds in this instance (the strip went beyond what is shown here). If you look carefully you can see that I’ve used a sheet of 4x5 cut down the middle, so as to get bigger sections of test strip.
This isn’t easy to read, so I’ve created an illustration to exaggerate and clarify the point. In this second example 30 seconds is the chosen time:
You are now in a position to print and scrutinise your negatives from the personal film speed test. Use your standard time and look carefully at the shadow areas. The speed that gives good shadow detail (at what we call zone III) is your new personal film speed.
Into the field!
I said this was a post about doing, and, armed with your personal film speed, it is now time to get out with your Intrepid. Intrepids are field cameras after all. While I like the romantic idea of readers literally going to fields at this point, it is actually better and more convenient to stay much closer to home. I want you to make an exposure in conditions that have a ‘normal’ brightness range of four stops - i.e. that have important shadows at zone III and important highlights that fall on zone VII. By ‘important’ we mean an area that is visually legible, a surface that has detail we want to look at. This needs to be a certain size of course to qualify, so don’t worry too much about elements that will be too small to see in the print.
An ideal scenario is something like a white garage or shed door with shrubs (making their own shadows) in front of it. You will realise that as we are being picky about the tonal values of individual areas it is necessary to put your spot meter to use. Ensure that the incident circle of your meter is properly and fully situated on the area you are reading from.
When using our meter, we are trying to learn about the number of stops between our key elements. This is what we mean by finding out if our subject has a four stop brightness range. Let’s look again at our studio still life and try to put it into these terms.
Let’s say we take a spot meter reading from the umbrella and the values we get are 1/60 second and f8. Suppose our personal film speed is 250. If we expose our sheet of film at these values we will be placing the umbreal on zone V, as discussed at the start. Now we measure from the black softbox cover. Our light meter returns a reading of 1/15 second at f8. That is two stops lower than the umbrella, or zone III. The foil softbox inner meters at 1/125 second at f8. It is therefore falling on zone VI. If we expose the whole sheet from our original reading on the umbrella, we would be placing that on zone V, and the cover and inner would fall on III and VI respectively. In this example we only have a three stop brightness range, and the highlights fall lower than the example I’d like you to find.
Once you have exposed your garage door and shrub picture (or equivalent), develop it as you did previously and print it using your standard time. If our film speed test has held up, you should have a print with good shadow detail. However it is the highlights we now need to scrutinise. Is there satisfactory detail on the zone VII area? Does the zone VII appear as a light grey, giving a sense of brightness without being too bright? Or is it dull and lifeless?
Adjusting highlights through development
What can we do if we are not happy with our highlights? In order to answer this question, I now need to introduce you to a special property of film. Imagine a sheet of film in a development tray as it undergoes its chemical reaction. The shadow areas have received the least amount of light, and they are registered on the negative relatively quickly. They are not very dense. As development continues the highlights gradually take shape. They have been exposed more intensively and so take longer to form, again relatively speaking.
We can exploit this property of film, either by reducing or extending development to alter the look of our highlights. The zone system rule of thumb says that a 15% increase or reduction in development time will lead to a one stop expansion or contraction of the highlight zones. If we expose a ‘normal’, four stop brightness scene at our personal film speed and are content with how our zone VII appears, we need do nothing more. However, if we feel that our VII is more like a VI, we can use a development time with the 15% addition in order to shift our VIs into VIIs. We could also go the other way if our VIIs were more like VIIIs.
At this point I want to take a little breath and remind the reader that this is a brief introduction. I’m covering a lot of zone system practice very quickly and the reader should know that there is a lot more to investigate in terms of establishing a satisfactory development time. Some zone system books will advise you to shoot a series of sheets (or frames on roll film) in order to fine tune your highlight zones. Some will advise that the same scene is shot with an identical exposure multiple times, with different sheets developed at times using the 15% adjustment (indeed, our door and shrub scene would work very well for this).
I will leave the reader to investigate this further, but the key point is that our highlights can be fine tuned. Look again at your print. This should represent a four stop range and there should be a sound sense of a range of tones from rich blacks to light but fulsome highlights. If not, you will need to play with the development time.
If this sounds like hard work, then I remind the reader of what is at stake. You are in the process of creating a repeatable method for achieving, with confidence, a satisfactory print with a full range of tones (admittedly under ‘average’ brightness conditions). In my view, that’s something worth working towards.
The creative potential of not normal
What, then, happens when our subject does not conform to this theoretical four-stop brightness scenario? To answer this question is to appreciate the full creative power of the zone system, and is the real prize in zone system work.
I have one last practical task for you, and I wager that this will be the most fun. I’m going to have to assume that your highlights in the above example are in place. You will likely have a sense if they need work, but the following comes with the assumption that they are resolved. We are going to deliberately expand the zones using development.
To explain how this works, I’m going to use my studio example again. Doing so will complete the lesson and helps us keep the example consistent. There are other ways to think about this and I’ll mention more below. You will recall that the studio scene is limited to a three stop brightness range (you might want to look at the image above again). However in zone system film work we are not constrained to that range. We could use the special property of film that we discovered to expand the highlights. We could, for example, place our umbrella on zone V, but develop it to make that zone VII. This would have the advantage of preserving the ‘black’ quality of the soft box cover whilst creating a ‘white’ umbrella, i.e. one more consistent with our visual expectations. The zone system creatively overcomes the shortcomings of the scene, of its limited brightness range.
So what I’d like you to do is to pick a scene with a normal or less than normal brightness range and deliberately expand the highlights. A great example to use is a large leaf or leaves on a bush or tree whose surface falls on zone V or VI when shadows are placed on zone III or II. Expanding this surface to zone VII will make a much more satisfying print than if you simply stuck with zone V or VI. It is often said that a darkroom worker aims to make a print that possess a wide range of tones. That is the objective here.
In this piece the surfaces of the central leaves fell on the upper end of zone V and were expanded through development. They are closer to zone VII in the final print.
More zone system play
There is another way to explore the same idea, which leads to further, and now concluding thoughts about uses of the zone system. Photographs in themselves can be thought of as zones. That is, the sum total of all their tones will fall roughly into one of the zones. Consider the image below, made from a section of chalk drawings on a grid of slabs.
The chalk circle three slabs up from the bottom in the centre was placed on zone VI. We might think of the image as a whole having a zone VI ambiance, even though there is evidently a wider range of tones within individual areas. That gives one rendition of the scene, but we are free to interpret it how we want, and that means meditating on other zones. Here is the same scene, exposed identically, but expanded to zone VII using development:
I did this as part of my highlight testing, so it is hardly ambitious in a creative sense. But you will see the potential: who is to say this couldn’t be a zone III image. Or a Zone VIII one. What would it look like? Would it fit in with your idea of what a print should look like? Why not try out such exposures and challenge yourself? Working with our Intrepid’s, sheet by sheet, and now with the zone system, we have huge creative play at our disposal.
It would be remiss of me not to conclude by pointing out there is one much more mundane use of the zone system I have not yet mentioned, and that is contracting highlights when the brightness range exceeds normal. The truth is that brightness ranges will often easily exceed our film’s ability to capture them, but with the zone system we have a way of reducing development and taming recalcitrant highlights, whilst still achieving open shadows and satisfying blacks. The zone system is a practical solution to our medium’s shortcomings and a springboard for personal vision.
It is my sincere hope that what I have written in this post has expanded your ideas as to what is achievable with your Intrepid camera and our wonderful medium of film. Even if you have only participated by reading and working on your understanding of what the zone system is, I hope you have glimpsed something of what can be achieved with a little work, practice and patience. What matters in the end is your own artistic vision, and the zone system is a fine way to put your camera to use in exploring it.
I think there is a lot to be gained from engaging in only parts of the above, especially film speed testing, but the fact is the zone system is large and somewhat formidable subject. If this post has piqued your interest, here are some fine and reliable sources for further reading:
Ansel Adams, The Negative (Bulfinch, 1995)
John Blakemore, John Blakemore’s Black and White Photography Workshop (David & Charles, 2005)
Ralph W. Lambrecht and Chris Woodhouse, Way Beyond Monochrome (Focal Press, 2010)