The Blog: See what
Sigma is saying.

06.02.2011

What is light? It’s often defined as the wavelengths of its electromagnetic radiation by those who know these things—they’re called physicists by the way. Big deal, huh? That doesn’t help us make beautiful pictures. So what is light? Really? Light is the stuff photographs are made of. So rather than go the scientific route and define light in accurate though in practicality meaningless ways; let’s talk about its qualities, describe them, learn to recognize them and then how to create them.

Harsh Light

In nature, harsh light is found on sunny days with a clear, cloudless skies. Subjects in harsh light cast sharply defined shadows that are usually quite dark when compared to the highlights of the subject. Here the sun backlights memorial tiles from 9/11 hanging on a chain link fence casting harsh shadows in the foreground.

 

This close up of the cast shadows shows their sharp edges. Note that the shadows in the foreground are less distinct that those toward the back. That’s because the tiles attached to the top of the fence are farther away from the ground.

Harsh light always happens when the source of light is smaller in relationship to the size of the subject. While the sun is 85,000 miles in diameter, it’s also a long, long ways away, about eight and a half light minutes. (That’s 186,282 miles per second times 510 seconds for the physicists.) For the photographers it means it’s small enough that holding your thumb up at arm’s length covers it up. Any source of illumination or light that you can cover with your thumb at arm’s length will produce harsh light.

This portrait was made in harsh light. The sun is high in the sky. The shadows around Laura’s head and under her chin are sharp telling us the light is harsh.

 

Qualities

Harsh light is very directional. Distinct shadow edges do a great job of revealing texture like the ruts in the ground of this construction site.

 

The “golden light” of late afternoons is harsh light that is warm in color, and very directional, skimming the earth from an almost horizontal angle. It tends to be dramatic as well illuminating part of the subject while the rest falls into deep shadow.

The only way to know for sure that a photograph is made in harsh light is to find distinct shadow edges. A transition between highlight and shadow that is very short defines the light as harsh. This is called the shadow edge transition. The shadow under the window box in this photograph from Orvieto, Italy shows the light is harsh.

See for yourself

The “rule of thumb” mentioned earlier, works for determining if a light source is small enough to produce harsh light. Sometimes it’s really tricky to see the shadow edge. Think about light falling on a curved surface. There isn’t anything to create a shadow so there is no way to tell by looking what the quality of light is. An easy way to check is to hold your index finger of one hand above the palm of the other.

Is the shadow edge clearly defined? Then the light is harsh.

 

If the edge is indistinct the light is soft.

 

Harsh light can create drama, mood and in this case nothing more than an interesting shadow on a hardwood floor.

In my next post on the Sigma Pros blog, the subject is soft light. Until then keep seeing and making great photographs!

light 1 |līt|
noun

1 the natural agent that stimulates sight and makes things visible : the light of the sun | [in sing. ] the street lamps shed a faint light into the room.

  • a source of illumination, esp. an electric lamp : a light came on in his room.
  • ( lights) decorative illuminations : Christmas lights.
  • a traffic light : turn right at the light.
  • [in sing. ] an expression in someone’s eyes indicating a particular emotion or mood : a shrewd light entered his eyes.
  • the amount or quality of light in a place : the plant requires good light | in some lights she could look beautiful.

Visible light is electromagnetic radiation whose wavelength falls within the range to which the human retina responds, i.e., between about 390 nm (violet light) and 740 nm (red). White light consists of a roughly equal mixture of all visible wavelengths, which can be separated to yield the colors of the spectrum, as was first demonstrated conclusively by Newton. In the 20th century it has become apparent that light consists of energy quanta called photons that behave partly like waves and partly like particles. The velocity of light in a vacuum is 299,792 km per second.

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  1. Thanks Kevin for this very interesting article.