Light is the essence of photography.

The purest definition of photography dates to the early Greek word “photos;” which means “drawing with light.”  Today, we define photography as “the science, art, application and practice of creating durable images by recording light or other electromagnetic radiation, either electronically by means of an image sensor, or chemically by means of a light-sensitive material such as photographic film.”  Indeed, without light, we cannot easily see; either with our natural eyes or with standard photographic equipment.

The most abundant source of light available is our Sun, located roughly 93 million miles from Earth.  The Sun, as a source of radiant light, is sufficient to illuminate at least a portion of the earth at all times.   Depending on where you are on the earth, you can experience its full power or a directional, reduced power based on its rising or setting positions.  Its hue can change too, as it mixes with various gases in our atmosphere.  This can also have an impact on its heat index. The quality of the sunlight can also vary based on whether there are sufficient clouds in the sky to block or scatter the rays of light.  Some of the most majestic images are witnessed when the sun’s rays peer through an opening in the clouds.   These rays can also be exaggerated when backlit with morning fog.  Matched only by imitation in art, Nature provides us with the most unmistakable expression of majestic light.

In photography, to emulate this majestic light, we have to study the impact that light can have on film.  (The term “film” is used to represent any image recording device currently in use that captures light.)   To be an effective photographer, you must understand the characteristics of light and how to use it to achieve your desired outcome.  And, therein lies the problem with using the Sun as a consistent source of light.  It is not consistent.

Nature controls the sun and she doesn’t always play fair.  Therefore, to create an even playing field, scientists developed a means of creating artificial light to compliment the photographer in various situations in which the sun was not a sufficient source. (IE.  In a dark, poorly lit, or night-time environment.) The basic term was coined, “Flash.”

As described above, the basic characteristics of light are Strength, Temperature/Color, Direction, and Quality.  These characteristics are consistent regardless of whether the light is created by flash or occurring naturally. (From hence-forward, the term “Flash” will be used to describe all sources of mechanically induced pops of light…ie. Speedlights or Strobes)

Strength

In theory, the strength of the Sun and its impact on the Earth is directly proportional to the position of the sun in the sky and not the distance between the subject and the source.  This is believed to be true since the distance between the Sun and the Earth remains constant.  However, the strength or intensity of the sun light, can have different affects in photography based on its position, ie. High-noon, dusk or dawn, or any variation in between.

As photographers, we tend to enjoy the impact of the “golden hour” sun when its either at is set or rise.  Because, during this time, it is a lesser intense light than at high noon.

To emulate the ability to have varying strengths of light, Flash devices have settings that allow us to adjust a dial that will modify the intensity of the beam as well.   Many of these settings range from Full power to 1/256th power of the original output. 

But there are also additional resources available to those using artificial light; resources such as the Inverse Square Law. (The inverse-square law, in physics, is any physical law stating that a specified physical quantity or intensity is inversely proportional to the square of the distance from the source of that physical quantity.)

For Photographers, this basic assessment states that distance can also be used to increase or decrease the intensity of a beam.  This can easily be witnessed using an inexpensive flashlight.  If you stand 1 foot from a bare white wall and shine the beam of light on the wall, you will notice an intense small circle of light.  Now, while maintaining the same position, step backwards about 3-4 feet.  Notice that the beam on the wall gets wider and less bright.  The intensity of the beam is being affected by the changing distance.

Note: there are various affects that can occur using a combo of power output and distance.

Understanding this is crucial to using distance as an additional method to control intensity in Flash Photography. In Natural light photography, without additional equipment, using distance to affect the light intensity is impractical.

Recap: 

• Natural light Photographer can use the position of the sun in the sky to control the intensity of the light.

• Photographers using Flash can control the intensity of the light by using any combo of Distance of Light source to Subject (Inverse Square Law) and the direct power settings of the flash.

Temperature

The kelvin is often used in the measure of the color temperature of light sources. Color temperature is based upon the principle that a black body radiator emits light whose color depends on the temperature of the radiator. Black bodies with temperatures below about 4000 K appear reddish, whereas those above about 7500 K appear bluish. Color temperature is important in the fields of image projection and photography, where a color temperature of approximately 5600 K is required to match "daylight" film emulsions. The Sun closely approximates a black-body radiator. The effective temperature, defined by the total radiative power per square unit, is about 5780 K. The color temperature of sunlight above the atmosphere is about 5900 K.

As the Sun crosses the sky, it may appear to be red, orange, yellow or white, depending on its position. The changing color of the Sun over the course of the day is mainly a result of the scattering of light.  The blue color of the sky is caused by the scattering of the sunlight by the atmosphere, which tends to scatter blue light more than red light.  Some early morning and evening light (golden hours) have a lower color temperature due to increased low-wavelength light scattering. (Wikipedia)

So for us, this is the function of the White Balance.  Playing around with this feature can create different hues as the camera interprets the Kelvin of light based on the setting created in camera.

Photographers using flash (Strobists) must be equally aware of this feature and must be able to match the artificial light to the appropriate Kelvin to blend Ambient (Sunlight or existing light) with Flash.  And also, Strobists can add Gels (a thin translucent material of varying colors) to the flash to aid in changing the hues or temperature of the light on film.

Direction

As stated earlier, the direction of the Sunlight or the placement of the Sun in the sky, has a specific impact on the intensity of the light.  However, direction also plays an important role in the placement of shadows.  Shadow placement in Photography is just as important as light itself.

Controlling the direction of light is extremely important for a photographer.  By controlling light, you inversely control darkness. Blending light and darkness into an image is an artistic expression mastered by the Painters of the Renaissance, like Leonardo da Vinci, Caravaggio, and Rembrandt. 

Chiaroscuro means “light to dark” in Italian.  Chiaroscuro also is used in cinematography to indicate extreme low key and high-contrast lighting to create distinct areas of light and darkness in films, especially in black and white films.  In photography, chiaroscuro can be achieved with the use of "Rembrandt lighting". (Rembrandt lighting is a lighting technique that is used in studio portrait photography. It can be achieved using one light and a reflector, or two lights, and is popular because it is capable of producing images which appear both natural and compelling with a minimum of equipment. Rembrandt lighting is characterized by an illuminated triangle under the eye of the subject on the less illuminated side of the face. It is named for the Dutch painter Rembrandt, who often used this type of lighting.) (Wikipedia)

Natural light shooters are limited in this type of control to the time of day they wish to conduct a session.  Nature waits for no one.  So, the Natural Shooter lacks complete control in this area.  However, there are techniques and devices that can aid the experienced photographer in achieving the desired directional light.

Strobists can place their strobes at various heights and in specific directions to control how the light engages the subject.  In addition, Strobists can also add additional lighting to complement the lighting environment…in order words, to fill-in the areas of undesired darkness or to add lighting to create separation of subject and background.

Quality

Light quality can be divided into two categories: hard and soft.  Despite Intensity, Temperature and Direction, the Quality of Light is most important. The factors that impact the quality of light are: distance and the size of the light source.  And, a lessor known feature called, “Feathering;” which uses the angle between the illuminated object and the source to create a soft light….in other words, the skewing of light from the source or the dead-end of its effective light using the Inverse Square Law.  

Hard Light

Hard light can be defined as a small source of light.  And, while the Sun is a large object, it is 93 million miles from Earth.  The effective light is hard because the Sun, relative to the Earth, is a small source of light.  Hard light sources cast shadows that are very distinct.   The intensity of the beam creates very refined edges to the shadows it produces.  When striking a subject at an angle, this light can reveal well-defined details in photography.  These details could be undesirable in certain situations.

Soft Light

Contrary to hard light, soft light is defined from larger sources of light.  In order to create softer light, light must strike a larger source and scatter.  The scattered light is multi-directional, less intense, and produces less refined edges.   Often in Photography or Cinematography, soft light is created with diffusion material or Scrims.   Silk is one of the best and most often used material as if reflects light easily.

Even though smaller lights begin as hard light, proximity relative to the subject can impact the quality of light as well.  However, a softbox or large sheets of material that can scatter the light are usually a better source of creating soft light.  Soft light is a favorite for Portrait Photographers.

In nature, Clouds can be a natural scatter-box and can turn what would be hard direct light from the Sun into soft more pleasurable light.  This is why many portrait photographers enjoy shooting on Overcast days, where the clouds can serve as a huge source of diffusion.

Conclusion

Regardless of whether the photographer uses the Sun to light her subjects or Flash, understanding the characteristics of light is extremely important.  And, we must not just understand the characteristics of light itself but also the various sources that produce the kind of light we seek to use.  As the Sun, which is the most abundant source, is not easily controlled, determining which type of light to use is often overwhelming.  Light can be uneven on some images, create hotspots on others, and/or unwanted shadows; and knowing what caused it and how to correct it, are crucial factors to becoming a well-rounded photographer.  

As a Strobist, it is my belief that every Photographer should have in her bag of tricks: diffusion panels, reflective panels, and deflective panels to block sun and create shade. This is true for us all, whether using the Sun as a primary source or Flash as a Primary source.  So, in closing, I hope each of us has found a new respect for light...regardless of the source.  I hope we can learn to appreciate it, study, and use it to our advantage.

It is my hope that this blog will give a minimal introduction to the four basic characteristics of light and that it will encourage you to engage in a deeper form of research and practice.  It is not my intent to promote one style of shooting over the over; nor did I intend to write a thesis on light and/or discuss every nuance of light’s impact.  In writing this, I only seek to encourage and promote a deeper sense of understanding.  I hope it motivates you to want to learn more.  

For more information, contact my Page through messenger.

Chas,