- Without light there would not be life on this planet. Light is also a prerequisite for photography
- The word photography means drawing with light. Photographers use two kinds of light: natural and artificial
- The aspects of light relevant to photography are its quantity, colour and duration
- Colour temperature is measured in degrees Kelvin. The higher temperatures are assigned to the blues while the cooler temperatures denote yellows and reds
And God said, “Let there be light,” and there was light. And God saw that the light was good. And God separated the light from the darkness. God called the light Day, and the darkness he called Night. And there was evening and there was morning, the first day.
According to the Bible, light is fundamental to life. It was created on the first day, before the plants or the animals or people. Light is the energy within all life on this planet. It enables photosynthesis which makes plant life possible, without which animal life would not exist either.
In the vacuum of the space, light travels at the velocity of 300,000 km/hour, or 186,000 mi/hour. On the earth, the speed of light is the same as in vacuum but it will take longer to get to you. The delay in arrival is due to the obstacles light meets on its way. In the atmosphere, light is forced to take the long route to reach its destination.
Light is indispensable to our everyday life and social functioning. It allows us to see our surroundings and prevents us from bumping in to things and other people. In a very real sense, light also keeps us sane. People living in areas with less year-round light – such as the Nordic countries and Canada – suffer from seasonal affective disorder. The lack of light is said to deplete the body’s serotonin reserves which creates depression and apathy, and may lead to serious consequences, including suicide.
We may, in fact, not realise how important light is to our existence. Philosophically speaking, it is doubtful whether we ever interact with anything but light. What we see in the world may not be the real world at all, or what we think it is. According to scientific knowledge, everything we perceive around us is emissions of electromagnetic energy exiting molecules of matter at different wavelengths. The individual chemical elements, that this world is supposed to consist of, radiate differing wavelengths of light, making this object seem brighter and that object dimmer, or composed of distinct colours. The objects in our world have unique spectographic signatures.
Light in Photography
In photography, we are also dealing with light. The word itself is derived from the Greek roots φωτός (phōtos), “light” and γραφή (graphé), “drawing”. Photography is drawing with light.
The light that we use as photographers is either from natural or artificial sources. Before the 20th Century, the only artificial light was derived from fire, in the form of a candle, oil lamp, gas light or similar. The mass-produced electric light became available in 1879, invented simultaneously by Thomas Edison in the United States and Joseph Swan in the UK. A 100-watt electric lamp could emit the equivalent light of a 120 candles. Suddenly, the world seemed like a much brighter place.
Artificial light allowed productive work as well as entertainment after dark. It was also used successfully as a decorative element both indoors and outdoors. For photographers, inexpensive artificial light sources made it possible to photograph anything from journalistic portraits to architecture and fashion in wonderful detail at all hours of the day and night. Using man-made lighting in photography also meant that it was more important than ever to study and learn about light and “drawing with light”.
Aspects of Light
Despite light being the most essential requirement for photography, it is also something that novice photographers may not fully appreciate. Technically speaking, when we photograph, it’s not the objects of the world that we are recording. Instead, we capture the light reflecting from these objects.
The aspects of light immediately relevant to a photographer are its quantity, colour and duration. Without at least a minimal quantity of light there is no photograph. Although the sensor technology has progressed to an amazing degree, and we are able to take photos in near-darkness, at incredible ISOs, it is still always better to arrange to take your photos at a time of day when there is ample ambient light. If this is not possible, you must make sure that you have with you, or at your disposal, artificial light and that you know how to utilise it for the effect that you wish to accomplish.
The colour of the light is critical in photography. Because our eyes are adaptive, and able to see almost any light as “normal”, we may not realise that our cameras lack this ability. The camera sensor, or film, is much simpler than our eyes and cannot react to a wrong colour balance by interpreting it as white – unless we tell it to. The sensor manufacturing has gone forwards in leaps and bounds in recent years, and it is now possible to rely on auto white balance in nearly all situations. You will also be able to correct the white balance of your images while post processing them. The white balance of a raw file is completely alterable after-the-fact but even if you shoot in JPEG you can still affect the colour balance of your images, just to a lesser degree.
In colour-critical photography, such as fashion or product photography, the white balance has to be adjusted manually every time the light changes – which might be dozens of times during a photoshoot if the photography happens outdoors. For less colour-finicky shooting, it is important to check the colour tone of the images periodically and to adjust the camera settings accordingly – or to photograph in raw always.
The duration of the light is relevant to flash photography. The strength of the flash light is dependant on the duration of the pulse that the flash unit gives. Longer pulses give out more light than shorter ones. Flash light is normally used in situations where ambient lighting is insufficient. It can also be used for artistic purposes, to freeze movement when, for instance, photographing people walking on the street. The people closest to the camera, lit by the flash, are frozen in their movement while the people farther away will have been captured with motion blur because they are lit by the existing light. For technical tricks like these, a good grasp of the difference between the flash light and the ambient light is required.
What is light
Light is electromagnetic radiation. The visible light – with which we mostly operate as photographers – is only a tiny portion of the totality of this radiation.
All radiation moves in waves, and it is the length of the waves that determines what kind of radiation we’re talking about, and whether we can see it. The visible part of the electromagnetic radiation starts at 400 nanometers and ends at 700 nanometers. The radiation with the longest wavelengths are the radio waves. Their wavelengths can stretch from one millimeter to hundreds of kilometers. At the shorter end, the gamma rays have wavelengths of 1/100,000,000 mm, and the so-called cosmic rays have even shorter wavelengths than this.
Out of the narrow band of wavelengths between 400 and 700 nm, the visible spectrum, our eyes are most sensitive to the middle area. For humans, the yellow-green colour, at 550 nm, is the easiest colour to see. The visual sensitivity deteriorates as we move towards the edges of the visible band, and is the weakest for violet (the shortest visible wavelength) and red (the longest visible wavelength).
The colours that we see around us are not a part of the natural world but created in our brains. The wavelengths that we perceive as various colours do not, in themselves, have any colour. The colour is generated in our minds as a response to the waves.
White light is a composite of all visible colours. These colours can be seen separately when the light is made to travel through a prism or when it shines through millions of raindrops, which refract them, forming a rainbow.
In photography, colour temperatures are measured in degrees Kelvin, on a scale from 1000 to 10,000. The colours with warmer tones (yellowish-white to red) are the ones with lower Kelvin temperatures, anything from 2700 to 3000 K. Among these “cool” colours are candle and tungsten light, as well as the colour of sunsets and sunrises. The colours with a higher temperature (5000K and upwards) include the blue sky at 10,000K and a shade under a blue sky at 7500K. The temperature of the white mid-day light is 5500K.
The longer the wavelength of the light the cooler will the temperature of the light source be. The shorter wavelengths, on the other hand, are reflected in the higher colour temperatures. The actual physical colour temperatures are at variance with our emotional response to the colours. Our instinctual understanding of a colour seems opposite to the scientific description of it. We tend to feel that the yellow or red light sources are warmer than the cool blues. The error of our thinking is made clear when we observe a flame of fire in a fireplace or a candle. The blue part of the flame is always much hotter than the yellow one.
The Kelvin system is a reliable way of describing colours. The individual temperature assigned to each colour is based on the colour that an opaque, non-reflective material (also known as black-body) emits at that temperature when heated up: when you know the temperature of the heated object you will also know the colour that it radiates.
How to Learn about Photography
A photographic image is made up of light captured by a light-sensitive surface. The surface can be in the form of a digital sensor, plastic film or even a glass plate treated with silver salts, as in the early years of photography during the 19th century. To consistently make pleasing photographs, the photographer needs to posses a proficiency in both the technical and the aesthetic aspects of his or her craft.
An aesthetic eye is acquired through trial and error as a result of a long practical experience. Technical knowledge is of a more straightforward nature and can be gained by diligent study from books, videos and websites or, better yet, by attending courses run by real flesh-and-blood humans: there is nothing like communicating face-to-face with a person who can guide your practice and answer your questions.
Thorough learning takes a prolonged period of time and is never completely finished. Although everyone has their own approaches to learning, it might not be a waste of time to see how others have structured their knowledge acquisition. One of the best ways to master anything – including photographic concepts – is the Feynman method.
Richard P. Feynman (1918-1988) was an American theoretical physicist and Nobel-price winner in physics. According to Feynman, you haven’t really learned a topic if you can’t explain it in simple terms. Feynman’s learning technique is divided into four parts:
- Choose the topic you wish to learn about then study it. Write down what you know about the subject. Whenever you find out something new, add it to the list.
- Pretend you’re teaching the topic to a group of students or school children. Explain the matter to them in words that make sense to them.
- When you realise you can’t explain something in simple terms, study some more and try to fill in the gaps in your knowledge.
- Use simple language and analogies when explaining the concept. Go back to the blackboard and demonstrate the matter to your “class” again, this time breaking down the contents to even simpler concepts than the first time.
The Feynman technique is very useful for any photography student, or even a professional photographer, who wishes to gain a deep understanding of the principles, techniques and the art of photography.
Sebastian Conran and Mark Bond: Somabasics: Lighting. (Soma, 2000)
Michael Freeman: Collins Photography Workshop: Light. (Collings, 1988)
Seasonal affective disorder: https://en.wikipedia.org/wiki/Seasonal_affective_disorder
Learn Anything In Four Steps With The Feynman Technique: https://curiosity.com/topics/learn-anything-in-four-steps-with-the-feynman-technique-curiosity/
All photos copyright Markus Jaaskelainen 2018.