Are black-and-white photographs really black and white?

Black-and-white photography is somewhat of a strange term, because it alludes to the fact that the photograph is black-AND-white. However black-and-white photographs if interpreted correctly would mean an image which contains only black and white (in digital imaging terms a binary image). Alternatively they are sometimes called monochromatic photographs, but that too is a broad term, literally meaning “all colours of a single hue“. This means that cyanotype and sepia-tone prints, are also to be termed monochromatic. A colour image that contains predominantly bright and dark variants of the same hue could also be considered monochromatic.

Using the term black-and-white is therefore somewhat of a misnomer. The correct term might be grayscale, or gray-tone photographs. Prior to the introduction of colour films, B&W film had no designation, it was just called film. With the introduction of colour film, a new term had to be created to differentiate the types of film. Many companies opted for the use terms like panchromatic, which is an oddity because the term means “sensitive to all visible colors of the spectrum“. However in the context of black-and-white films, it implies a B&W photographic emulsion that is sensitive to all wavelengths of visible light. Afga produced IsoPan and AgfaPan, and Kodak Panatomic. Differentially, colour films usually had the term “chrome” in their names.

Fig.1: A black-and-white image of a postcard

All these terms have one thing in common, they represent the shades of gray across the full spectrum from light to dark. In the digital realm, an 8-bit grayscale image has 256 “shades” of gray, from 0 (black) to 255 (white). A 10-bit grayscale image has 1024 shades, from 0→1023. The black-and-white image shown in Fig.1 illustrates quite aptly an 8-bit grayscale image. But grays are colours as well, albeit without chroma, so they would be better termed achromatic colours. It’s tricky because a colour is “a visible light with a specific wavelength”, and neither black nor white are colours because they do not have specific wavelengths. White contains all wavelengths of visible light and black is the absence of visible light. Ironically, true blacks and true whites are rare in photographs. For example the image shown in Fig.1 only contains grayscale values ranging from 24..222, with few if any blacks or whites. We perceive it as a black-and-white photograph only because of our association with that term.

Myths about travel photography

Travel snaps have been around since the dawn of photography. Their film heyday was likely the 1950s-1970s when photographs taken using slide film were extremely popular. Of course in the days of film it was hard to know what your holiday snaps would look like until they were processed. The benefit of analog was of course that most cameras offered similar functionality, with the aesthetic provided by the type of film used. While there were many differing lenses available, most cameras came with a stock 50mm lens, and most people travelled with a 50mm lens, possibly a wider lens for landscapes, and later zoom lenses.

With digital photography things got easier, but only in the sense of being able to see what you photograph immediately. Modern photography is a two-edged sword. On one side there are a lot more choices, in both cameras, and lenses, and on the other side digital cameras have a lot more dependencies, e.g. memory cards, batteries etc., and aesthetic considerations, e.g. colour rendition. Below are some of myths associated with travel photography, in no particular order, taken from my own experiences travelling as an amateur photographer. I generally travel with one main camera, either an Olympus MFT, or Fuji X-series APS-C, and a secondary camera, which is now a Ricoh GR III.

The photographs above illustrate three of the issues with travel photography – haze, hard shadows, and shooting photographs from a moving train.

MYTH 1: Sunny days are the best for taking photographs.

REALITY: A sunny or partially cloudy day is not always congenial to good outdoor photographs. It can produce a lot of glare, and scenes with hard shadows. On hot sunny days landscape shots can also suffer from haze. Direct sunlight in the middle of the day often produces the harshest of light. This can mean that shadows become extremely dark, and highlights become washed out. In reality you have to make the most of whatever lighting conditions you have available. There are a bunch of things to try when faced with midday light, such as using the “Sunny 16” rule, and using a neutral density (ND) filter.

MYTH 2: Full-frame cameras are the best for taking travel photography

REALITY: Whenever I travel I always see people with full-frame (FF) cameras sporting *huge* lenses. I wonder if they are wildlife or sports photographers? In reality it’s not necessary to travel with a FF camera. They are much larger, and much heavy than APS-C or MFT systems. Although they produce exceptional photographs, I can’t imagine lugging a FF camera and accessories around for days at a time.

MYTH 3: It’s best to travel with a bunch of differing lenses.

REALITY: No. Pick the one or two lenses you know you are going to use. I travelled a couple of times with an extra super-wide, or telephoto lens in the pack, but the reality is that they were never used. Figure out what you plan to photograph, and pack accordingly. A quality zoom lens is always good because it provides the variability of differing focal lengths in one lens, however fixed focal length lenses often produce a better photograph. I would imagine a 50mm equivalent is a good place to start (25mm MFT, 35mm APS-C).

MYTH 4: The AUTO setting produces the best photographs.

REALITY: The AUTO setting does not guarantee a good photograph, and neither does M (manual). Ideally shooting in P (program) mode probably gives the most sense of flexibility. But there is nothing wrong with using AUTO, or even preset settings for particular circumstances.

MYTH 5: Train journeys are a great place to shoot photographs.

REALITY: Shooting photographs from a moving object, e.g. a train requires the use of S (shutter priority). You may not get good results from a mobile device, because they are not designed for that. Even using the right settings, photographs from a train may not always seem that great unless the scenery allows for a perspective shot, rather than just a linear shot out of the window, e.g. you are looking down into valleys etc. There is issues like glare, and dirty windows to contend with.

MYTH 6: A flash is a necessary piece of equipment.

REALITY: Not really for travelling. There are situations you could use it, like indoors, but usually indoor photos are in places like art galleries and museums who don’t take kindly to flash photography, and frankly it isn’t needed. If you have some basic knowledge it is easy to take indoor photographs with the light available. Even better this is where mobile devices tend to shine, as they often have exceptional low-light capabilities. Using a flash for landscapes is useless… but I have seen people do it.

MYTH 7: Mobile devices are the best for travel photography.

REALITY: While they are certainly compact and do produce some exceptional photographs, they are not always the best for travelling. Mobile devices with high-end optics excel at certain things, like taking inconspicuous photographs, or in low-light indoors etc. However to get the most optimal landscapes, a camera will always do a better job, mainly because it is easier to change settings, and the optics are clearly better.

MYTH 8: Shooting 1000 photographs a day is the best approach.

REALITY: Memory is cheap, so yes you could shoot 1000 frames a day, but is it the best approach? You may as well strap a Go-Pro to your head and video tape everything. At the end of a 10-day vacation you could have 10,000 photos, which is crazy. Try instead to limit yourself to 100-150 photos a day, which is like 3-4 36 exposure rolls of film. Some people suggest less, but then you might later regret not taking a photo. There is something about limiting the amount of photos you take and instead concentrate on taking creative shots.

MYTH 9: A tripod is essential.

REALITY: No, its not. They are cumbersome, and sometimes heavy, and the reality is that in some places, e.g. atop the Arc de Triomphe, you can’t use a tripod. Try walking around the whole day in a city like Zurich during the summer, lugging a bunch of camera gear, *and* a tripod. For a good compromise, consider packing a pocket tripod such as the Manfrotto PIXI. In reality cameras have such good stabilization these days that in most situations you don’t need a tripod.

MYTH 10: A better camera will take better pictures.

REALITY: Unlikely. I would love to have a Leica DLSR. Would it produce better photographs? Maybe, but the reality is that taking photographs is as much about the skill of the photographer than the quality of the camera. Contemporary cameras have so much technology in them, learn to understand it, and better your skills before thinking about upgrading a camera. There will always be new cameras, but it’s hard to warrant buying one.

MYTH 11: A single battery is fine.

REALITY: Never travel with less than two batteries. Cameras use a lot of juice, because features like image stabilization, and auto-focus aren’t free. I travel with at least 3 batteries for whatever camera I take. Mark them as A, B, and C, and use them in sequence. If the battery in the camera is C, then you know A and B need to be recharged, which can be done at night. There is nothing worse than running out of batteries half-way through the day.

MYTH 12: Post-processing will fix any photos.

REALITY: Not so, ever heard of the expression garbage-in, garbage-out? Some photographs are hard to fix, because not enough effort was taken when they were taken. If you take a photograph of a landscape with a hazy sky, it may be impossible to post-process it.

The facts about camera aspect ratio

Digital cameras usually come with the ability to change the aspect ratio of the image being captured. The aspect ratio has a little to do with the size of the image, but more to do with its shape. The aspect ratio describes the relationship between an image’s width (W) and height (H), and is generally expressed as a ratio W:H (the width always comes first). For example a 24MP sensor with 6000×4000 pixels has an aspect ratio of 3:2.

Choosing a different sized aspect ratio will change the shape of the image, and the number of pixels stored in it. When using a different aspect ratio, the image is effectively cropped with the pixels outside the frame of the aspect ratio thrown away. 

The core forms of aspect ratios.

The four most common examples of aspect ratios are:

  • 4:3
    • Used when photos to be printed are 5×7″, or 8×10″.
    • Quite good for landscape photographs.
    • The standard ratio for MFT sensor cameras.
  • 3:2
    • The closest to the Golden Ratio of 1.618:1, which makes things appear aesthetically pleasing.
    • Corresponds to 4×6″ printed photographs.
    • The default ratio for 35mm cameras, and many digital cameras, e.g FF, APS-C sensors.
  • 16:9
    • Commonly used for panarama’s, or cinematographic purposes.
    • The most common ratio for video formats, e.g. 1920×1080
    • The standard aspect ratio of HDTV and cinema screens.
  • 1:1
    • Used for capturing square images, and to simplify scenes.
    • The standard ratio for many medium-format cameras.
    • Commonly used in social media, e.g. Instagram.

How an aspect ratio appears on a sensor is dependent on the sensors default aspect ratio.

Aspect ratios visualized on different sensors.

Analog 35mm cameras rarely had the ability to change the aspect ratio. One exception to the rule is the Konica Auto-Reflex, a 35mm camera with the ability to switch between full and half-frame (18×24mm) in the middle of a roll of film. It achieved this by moving a set of blinds in to change the size of the exposed area of the film plane to half-frame.

Could blur be the new cool thing in photography?

For many years the concept of crisp, sharp images was paramount. It lead to the development of a variety of image sharpening algorithms to suppress the effect of blurring in an image. Then tilt-shift appeared, and was in vogue for a while (it’s still a very cool effect). Here blur was actually being introduced into an image. But what about actually taking blurry images?

I have been experimenting with adding blur to an image, either through the process of  manually defocusing the lens, or by taking a picture of a moving object. The results? I think they are just as good, if not better than if I had “stopped the motion”, or created a crisp photograph. We worry far too much about defining every single feature in an image, and too little on a bit of creativity. Sometimes it would be nice to leave something in an image that inspires thought.

Here’s an example of motion-blur, a Montreal Metro subway car coming into a platform. It is almost the inverse of tilt-shift. Here the object of interest is blurred, and the surround area is kept crisp. Special equipment needed? Zip.

More on Mach bands

Consider the following photograph, taken on a drizzly day in Norway with a cloudy sky, and the mountains somewhat obscured by mist and clouds.

Now let’s look at the intensity image (the colour image has been converted to 8-bit monochrome):

If we look at a region near the top of the mountain, and extract a circular region, there are three distinct regions along a line. To the human eye, these appear as quite uniform regions, which transition along a crisp border. In the profile of a line through these regions though, there are two “cliffs” (Aand B) that marks the shift from one region to the next. Human eyes don’t perceive these “cliffs”.

The Mach bands is an illusion that suggests edges in an image where in fact the intensity is changing in a smooth manner.

The downside to Mach bands is that they are an artificial phenomena produced by the human visual system. As such, it might actually interfere with visual inspection to determine the sharpness contained in an image.

Aesthetically motivated picture processing

For years I wrote scientific papers on various topics in image processing, but what I learnt from that process was that few of the papers written are actually meaningful. For instance, in trying to create new image sharpening algorithms many people forgot the whole point of sharpening. Either a photographer strives for sharpness in an entire image or endeavours to use blur as a means of focusing the attention on something of interest in the image (which is in focus, and therefore sharp). Many sharpening algorithms have been developed with the concept of sharpening the whole image… but this is often a falsehood. Why does the photo need to be sharpened? What is the benefit? A simple sharpening with unsharp masking (which is an unfortunate name for a filter) works quite well in its task. But it was designed at a time when images were small, and filters were generally simple 3×3 constructs. Applying the original filter to a 24MP 4000×6000 pixel image will make little, if any difference. On the other hand, blurring an image does nothing for its aesthetics unless it is selective, in essence trying to mimic bokeh in some manner.

Much of what happens in image processing (aside from machine vision) is aesthetically based. The true results of image processing cannot be provided in a quantitative manner and that puts it at odds with scientific methodology. But who cares? Scientific thought in an academic realm is far too driven by pure science with little in the way of pure inventing. But alas few academics think this way, most take on the academic mantra and are hogtied to doing things in a specified way. I no longer prescribe to this train of thoughts, and I don’t really know if I ever did.

aesthetic appeal, picture of Montreal metro with motion blur

This picture shows motion blur which results from a moving subway car, whilst the rest of the picture remains in focus. The motion blur is a part of the intrinsic appeal of the photograph – yet there is no way of objectively quantifying the aesthetic value – it is something that can only be qualitatively and subjectively evaluated.

Aesthetically motivated Image processing is a perfect fit for photographs because while there are theoretical underpinnings to how lenses are designed, and technical principles of how a camera works, the ultimate result – a photograph, is the culmination of the mechanical ability of the camera and the artistic ability of the photographer. Machine vision, the type used in manufacturing facilities to determine things like product defects is different, because it is tasked with precision automated photography in ideal controlled conditions. To develop algorithms to remove haze from natural scenes, or reduce glare is extremely difficult, and may be best taken when thee is no haze. Aesthetic-based picture processing is subjectively qualitative and there is nothing wrong with that. It is one of the criteria that sets humans apart from machines – the inherent ability to visualize things differently. Some may find bokeh creamy while others may find it too distractive, but that’s okay. You can’t create an algorithm to describe bokeh because it is an aesthetic thing. The same way it’s impossible to quantify taste, or distinguish exactly what umami is.

Consider the following quote from Bernard Berenson (Aesthetics, Ethics, and History) –

‘The eyes without the mind would perceive in solids nothing but spots or pockets of shadow and blisters of light, chequering and criss-crossing a given area. The rest is a matter of mental organization and intellectual construction. What the operator will see in his camera will depend, therefore, on his gifts, and training, and skill, and even more on his general education; ultimately it will depend on his scheme of the universe.’

Photographs and the craft of chance

Photographs are the encapsulation of our lives. They are snapshots, brief interludes into slices of time. Times long past. Memories of fighting in the trenches in WW1, the landings at Normandy, life in small Italian mountain villages. The best and worse of our histories. Photographs capture such fleeting moments that in most cases it would be impossible to reproduce. Photography is in its core essence the art of chance. Of being in the right place at the right time, of being able to capture just the right amount of photons entering the camera. Blink, and it could all be different. Before photographs our history was handed down through generations in stories, or paintings upon the wall. But neither of these is fleeting, they are thought-out, prescribed renditions of history. Photographs are not, they are raw, invoking, and often need no explanation. And while they could be considered by some to be art, they are crafted using tools which allow light to be captured. The true result is in natures control.

Capturing natural life is truly the essence of the craft of chance. That one photograph that captures an insect holding still, almost posing for the shot – blink and it will move on to its next feast.

The camera does not lie

There is an old phrase, “the camera does not lie“, which can be interpreted as both true and false. In historic photos where there was little done in the way of manipulation, the photograph often did hold the truth of what appeared in the scene. In modern photographs that are “enhanced” this is often not the case. But there is another perspective. The phrase is true because the camera objectively captures everything in the scene within its field of view. But it is also false, because the human eye, is not all seeing, perceiving the world in a highly subjective manner – focusing on the object (or person) of interest. Most photographs tend to contain far too much information, visual “flotsam” that is selectively discarded by the human visual system. The rendition of colours can also appear “unnatural” in photographs because of issues with white balance, film types (in analog cameras), and sensors (digital cameras). 

What the human eye sees (left) versus the camera (right)

A good example of how the human eye and camera lens perceive things differently is shown in the two photos above. The photograph on the right contains photographic perspective distortion (keystoning), where the tall buildings tend to “fall” or “lean” within the picture. The human eye (simulated on the left) on the other hand, corrects for this issue, and so does not perceive it.  To photograph a tall building, the camera is often tilted upward, and in position the vertical lines of the building converge toward the top of the picture. The convergence of vertical lines is a natural manifestation of perspective which we find acceptable in the horizontal plane (e.g. the convergence of railway tracks in the distance), but which seems unnatural in the vertical plane.

There are many other factors that influence the outcome of a picture. Some are associated with the physical abilities of a camera and its associated lenses, others the environment. For example the colour of ambient light (e.g. a colour cast created by the sun setting), perspective (the wider a lens the more distortion introduced), or contrast (e.g. B&W images becoming “flat”). While the camera does not lie, it rarely exactly reproduces the world as we see it. Or maybe we don’t perceive the world around us as it truly is.