I See The Light

January 21, 2019  •  Leave a Comment

I See The Light

By Marc F Alter

 

Photography: It’s All About Light

Ever since I started with photography, I have been told “It’s All About The Light”. I have often thought, what does this mean? In its simplest form, if I take a picture in a lightless room will I end up with just a black image? Likewise, if I take a picture of a polar bear in a snowstorm, will I end up with just a white image (provided he does not eat me first)? Most likely, yes in both instances.

 

In fact, the very definition of Photography (“the art or process of producing images by the action of radiant energy and especially light on a sensitive surface…[1]”) involves light. You cannot take a picture without some amount of light. When you click your camera’s shutter, light enters the lens and creates the image onto the film or sensor media. Without this light, there is no image.

 

In the past, we have discussed the Exposure Triangle and how to get good exposures. This, however, is not enough. Your understanding and use of light can be a deciding factor in determining if your image is spectacular (scoring a 9 of 9) or a terrible (scoring a 6 of 9 or worse).

 

What Is Light?

Light is actually a very complex subject. It’s more than just shining a light on something. Light is a form of electromagnetic energy that travels like a wave. It is part of an energy spectrum of long waves to short waves consisting of radio waves, microwaves, infrared waves, visible light, ultra violet light, x-rays and gamma rays. Scientifically, light has three main properties; Wavelength, Amplitude and Speed.

 

Wavelength represents what light we can see and what color it “sheds” on our subjects. As humans, we can only “see” light that falls within a limited wavelength (somewhere in the range of 300 to 800 nanometers) although various instruments and sensors (including our cameras) can detect, measure and capture light we cannot see. Amplitude represents the intensity and brightness of light. Although the speed of light is constant (in a vacuum it travels at 186,282 miles per second), different can wavelengths travel at different speeds as they travel through different mediums (like through particles in the atmosphere).

 

The Four Main Factors Of Light:

Photographically, light involves 4 main factors; (1) Intensity (2) Quality (3) Color and (4) Direction.

 

Light Intensity indicates how much light is present and its strength. Too much light and you need to shield your eyes. Not enough light and you may need to introduce another light source to see. There are several factors that affect light intensity. The amount of energy the light source radiates effects its strength as well as the distance from the light source to your subject. This light energy or output is typically measured in lumens. How does this light intensity affect your image capture workflow? Too little light and you will need to raise your exposure. Too much light and you will need reduce your exposure.

 

While light intensity is something that can be easily measured, Light Quality is more of a visual perception. At the extremes, light can be Soft or Hard. Soft Light usually comes from a light source that is bigger, diffused and/or farther away than the Subject, typically with multiple points of light coming from different directions.  Soft light gives evenly spread illumination with low contrast and smooth transitions from lights to darks, highlights to shadows. Shadows are shallow and allows colors to be more visible (saturated) and pronounced. Hard Light on the other hand, typically comes from a single, direct light source that is close to the Subject. As such it is harsh and directional. Hard light tends to increase contrast and produces long, shadows that are sharp with high contrasts.  Shadows are deep and color perception is reduced.

 

Similar to Light Quality, Light Color (also known as Light Temperature or Color Temperature) is both measurable and perceptual. It is typically measured using a Kelvin Scale but instead of measuring heat, Kelvins (expressed in Ks) are a Color Index, representing how we “experience” different light wavelengths.  As light sources emit light in different wavelengths, we “see” or “perceive” these light waves in different colors. Examples include Reds and Oranges at around 500-2000K, Yellows at around 2500-3500K, Daylight (Pure White) at 5000K and Blues at around 6500K+.

 

Photographically, these colors affect our mood and the mood perceived from our images. Red, Orange and Yellow hues give us a sense of warmth and calm while Blue to Black hues give us a sense of cold excitement. These color temperatures can have a great impact on our images and how our images are perceived. Depending on our lighting source and the color temperature it emits, we may experience a color cast that is unnatural and disturbing or use a color cast to create a desired feeling.

 

The Direction of Light is another important factor in Photography, especially when the light is not diffused. Lighting Direction represents the relationship between you (and your camera), your subject and the light source. There are three different types of Directional Lighting; Front Light, Side Light and Back Light.

 

Front Light is the most common as it luminates subjects evenly.  The down side of Front Lighting is sometimes it is considered flat as it reduces shadows (which typically adds interest and depth to our images).

 

Side Light is the next most common as it adds drama and texture to an image’s subject. Side Lighting also produces more depth to an image. With Side Lighting the greater the angle, the greater the shadows and the greater the contrast. Light set at a 30-45 degree angle, will produce more even results then light set at a 90 degree angle. Side Lighting may come from the left, right, top or bottom. Great care must be used with Side Lighting as it can easily add to an image (highlighting desired features) or detract from an image (highlighting undesired features).

 

Back Light is when the light source is behind your subject and the light is shinning directly into your camera’s lens. This often makes the background over exposed and your subject underexposed (silhouetted) and sometimes will also produce lens glare (Lens glare can vary depending on the angle of your light source as well as the size of your f-stop). Although difficult to use and control, Back Lighting can often add drama and great interest to a photo.

 

Types of Light

There are two main types of light, Natural Light and Artificial Light. Natural Light comes from two sources; the Sun (known as Sunlight) or the Moon (known as Moonlight). Natural Light (many times also referred to as Ambient Light or Available Light) does not require man-made equipment to be produced (its “free” to one and all). Great care however must be taken when using Natural Light as your light source as its intensity, quality, color & direction is constantly changing.

 

Natural Light is greatly affected by the weather. At the same time of day, clear sunny weather can produce great amounts of harsh light and cloudy, rainy weather can give softer more defused light.  You can use Natural Light to your advantage both outside as well as inside (as long as you have an opening or window to allow the light to enter).

 

There are several different definitions that help to define the types of Natural Light that occurs at different times of the day. Each with their own characteristics. Some of these include:

  • Daylight (Also known as Daytime) is when the Sun has risen and is at least 6 degrees above the horizon. During the day the Sun is high overhead. It emits strong and powerful hard light producing harsh illumination with high contrast and sharp transitions from lights and darks. Wavelengths are minimized with the result being that color casts are reduced. As the Sun is high in the sky, it comes in from straight overhead, producing low and short shadows. Color Temperature is approximately 6500k

 

  • Dappled Light is daylight that is filtered through tree leaves. The Sun is typically high in the sky and produces uneven diffusion and shadows as the light passes thru the leaves into the Subject.

 

  • Perpetual Daylight is when the Sun is above the horizon throughout the day. In these cases sunrise and dawn or sunset and dusk are very brief. This typically occurs when you are very close to the earth’s poles or when the summer equinox is approaching.

 

  • Twilight is when light is emitted before the Sun rises and after it has set. The Sun is either at the horizon or 18 degrees below. Morning Twilight is when the Sun is rising while Evening Twilight is when the Sun is setting. There are several different types of Twilights including:

 

  • Civil Twilight occurs right before the Sun rises or immediately after it has set. The Sun is either at the horizon or 6 degrees below. There is still enough light to be able to see objects using Natural Light. The sky is still bright. Clouds in the western sky are lit with reddish-orange sunlight while the eastern clouds are given a blueish-indigo cast. Depending on the season, in North America, Civil Twilight can last 20-30 minutes.

 

  • Nautical Twilight (taking its name from when stars would first appear in the sky and Sailors would look at these stars to calculate their bearings) occurs immediately after Civil Twilight when the sky has darkened to a deep blue tone, the horizon line can still be seen, and stars become visible. The Sun is 6 to 12 degrees below the horizon.

 

  • Astronomical Twilight occurs when the Sun is far below the horizon and the sky is darker. The Sun is 12 to 18 degrees below the horizon.

 

  • Perpetual Twilight occurs when the sun is below the horizon throughout the day, but never dips lower than 6 degrees below the horizon. Both sunrise and dawn or sunset and dusk are very brief. This can happen near the poles in the spring and fall.

 

  • Nighttime is when the Sun is at least 18 degrees below the horizon (you cannot see the Sun as the light source as it is below the horizon, so you will just have to take my word for it).

 

  • Perpetual Nighttime is when the Sun is more than 6 degrees below the horizon throughout the day. Like Perpetual Daylight, sunrise and dawn or sunset and dusk are very brief. This typically occurs when you are very close to the poles or when the winter solstice is approaching.

 

  • Magical Hours

 

  • Golden Hour occurs when the Sun is rising, and Civil Twilight is approaching. The Sun is 4 to 6 degrees below the horizon. The landscape starts to become illuminated and the sky starts to turn from reddish-orange to yellow (hence the name “Golden Hour”). The light will be soft, diffused and with low contrast as the Sun is still low in the sky.

 

  • Blue Hour occurs when the Sun is setting, and the end of Civil Twilight is approaching. The Sun is 4 to 6 degrees below the horizon. The horizon line is visible, the landscape is still lite and some of the brightest stars and closest planets are just becoming visible. Light becomes defused and the sky turns an intense, dark blue. Clouds can be illuminated with bright reddish-orange colors.

Artificial Light is when light comes from sources other than the Sun or Moon. With artificial Light, you typically have more control over the 4 different factors of light (Intensity, Quality, Color & Direction) then you would with Natural Light.

 

There are many different types of Artificial Light Sources (with more possibly being invented in the future). Each may have its own characteristics. Of these, the most common in use today are:

  • Incandescent Light (Tungsten) – Usually comes from common house light bulbs. These lights tend to have a warm color cast compared to natural daylight. Typically, this produces harsh light (which is why we commonly use lamp shades to soften or diffuse this light). Color Temperature approximately 2500 – 3500k (Warm White)

 

  • Fluorescent Light – Usually found in many commercial buildings and offices. In prior years these lights would give off a greenish hue but now there are several different types of Fluorescents, each giving off different color casts (cool or warm white, daylight, etc). With these different types, it would not be so surprising to find different bulbs in the same fixture. Color Temperature approximately 2700k to 6500k (typically Cool White)

 

  • CFL Curly Bulb (CFL) – The CFL (Compact Fluorescent Light) are typically found in warehouses or office buildings where lights are meant to be turned on for long periods of time. Recently they have also been appearing in households as replacements for Incandescent or Tungsten bulbs. CFLs are being phased out as they are hazardous to handle and difficult to dispose (they have mercury in them). Color Temperature approximately 3500k to 4500k (White to Cool White)

 

  • LED (Light Emitting Diode) – These lights are becoming extremely popular as replacements for CFLs as they are less expensive to buy and operate. They are being used in everything from flashlights to airplane lights. Like Fluorescent Lights, LED lights can come with different color casts (Soft White (2500K – 3000K), Bright White/Cool White (3500K – 4100K), and Daylight (5000K – 6500K).

 

  • Flash and Studio Strobe – Most on camera and off-camera Flash units and Studio Lights are designed to approximate Daylight (White Light) but some do give off a slightly cool Color Cast. As such, these typically have a Color Temperature of approximately 5000k.

 

  • Other lights – There can be other light sources that emit light with different Color Temperatures. Some of these are:

 

  • Fire (Candle Light, Oil Lamps, Kerosene/Paraffin Lamps, Lanterns, Torches, etc) – Used for thousands of years. Color Temperature approximately 1000k to 2000k (Warm Yellow Cast)

 

  • Metal Halide – This is a type of electrical lamp that produces light using an electric arc through a gaseous mixture of vaporized mercury and metal halides (metals with bromine or iodine) which emits a high intensity discharge of gas. Starting in the 1960s these lights have been used in automobile headlights, illuminating sports fields, parking lots and street lights. Color Temperature approximately 3000k to 20,000k

What Is White Balance?

No photographic discussion of Color Temperature would be complete without an understanding of White Balance. Basically, White Balance (WB) is a setting in your DSLR camera that allows you to control how the camera’s sensor reads the scene’s Color Temperature (Color Cast, Hue and Intensity of the Light Source) and interprets how this is used in the image.

 

As we have discussed, with Natural Light, different times of the day can produce light with different Color Temperatures. With Artificial Light, different Light Sources also emit different Color Temperatures. These different Color Temperatures range from very Warm to very Cool, often giving our images a Color Cast that is not true to the actual scene. Typically, we do not “see” these color casts as our minds automatically adjust what we see and “rationalize” these colors as “normal” for the scenes before use. Our DSLR cameras however are not as smart. The sensor captures only what it “sees”.

 

Most DSLR cameras have White Balance settings with the default set to “Auto”. This allows the camera to try and automatically adjust the image’s recorded colors. Most times the camera gets it right but depending on the WB compensation logic built into the camera and your intent, the colors captured may not be correct for your purpose.

 

We can compensate for these false color casts by adjusting the “White Balance”. This can be done both “In-Camera” when we are taking the picture and during “Post Processing” (as long as we are saving our images in Raw format).

 

In-Camera White Balance settings typically include the following:

  • Auto – Use this setting when you want your camera to try band make its best guess on the Color Cast for your images. You can also use this if you don’t understand the concept of White Balance and/or are too lazy to make the WB adjustments yourself.

 

  • Tungsten – This setting is used for shooting indoors under tungsten (incandescent) lighting. As Tungsten bulbs typically have a warm color temperature, this setting cools down the colors in your photos.

 

  • Fluorescent – This setting is also used for shooting indoors but when under fluorescent lights. As fluorescent lights typically have a cool Color Temperature, this setting warms up the colors in your photos.

 

  • Daylight/Sunny – This setting is used when outside on clear, sunny days when the Sun’s color temperature is white. Usually with this setting the camera will not adjust for this Color Temperature.

 

  • Cloudy – As clouds sometimes emit a cooler Color Temperature, this setting will typically warm up the image to better approach the white of “daylight”.

 

  • Flash – Like clouds, camera flashes can be slightly cool so this setting will slightly warm up the Color Temperature of your shots.

 

  • Shade – As the light under shade is usually cooler (bluer) than shooting in direct sunlight, this setting will generally warm up the Color Temperature of your shots.

 

  • Manual WB – In most cases, the above WB Presets can help to adjust the Color Cast of your scene during capture but even with these settings, the colors you capture may not be true or accurate. To compensate for this, you can use a White Card to measure the scene and then manually adjust the camera’s White Balance setting to capture accurate colors.

Some scenes can be more challenging than others when trying to correctly capture colors. If we are shooting and saving our images using the Raw Format, we can adjust any false Color Casts during our “Post Processing” workflow. Most good digital editing tools now contain White Balance or Color Temperature settings and sliders that are simple and easy to use. Depending on your expertise in these tools, you can even introduce a Color Cast that did not exist but that enhances the mood of your image.

 

How Do You Use Light?

Understanding the different aspects of light is the first step in determining how to use it. In both Image Capture and Post Processing, think about your subject and the mood you are trying to achieve. Use the 4 different factors of light (Intensity, Quality, Color & Direction) and determine how each of these will affect your image; both individually and combined. Some of the more common questions you may ask yourself are:

  • Is the light you are using going to enhance your image or detract from it?
  • Is the light illuminating your subject or competing with it?
  • Are you properly lighting your Subject or is the Subject your Light Source?
  • Are you trying to display a calm, serene scene or one of high drama and excitement and what Color Casts are you using to represent this?
  • Is your Light creating an even tone or harsh deep shadows?

Time of day and the light that is produced is critically important when taking pictures with Natural Light.

  • Daylight (High Noon)- the Sun is high in the sky
    • Intensity: When the Sun is high overhead, it emits strong and powerful illumination.
    • Quality: The Sun’s light is hard, producing harsh illumination with high contrast and sharp transitions from lights and darks.
    • Color: The Sun emits longer wavelengths, giving cool color hues. Although traveling through the same atmosphere, there is less distance and thus the effect of dust, moisture and other particles effecting different wavelengths are minimized. The result is that color casts are reduced.
    • Direction: As the Sun is high in the sky, it comes in straight, producing low and short shadows.

Many photographers believe this is the worst time of day to be taking pictures (especially for landscape and outdoor portrait images) as the Sun is typically high in the sky and thus produces harsh, intensive, top-down directional light.

Personally, I sometimes disagree with this concept as it depends on the type of picture you are looking to create. Sometimes harsh light might he better depending on your subject, especially if you’re trying to achieve a gritty or intense, exciting image. Harsh light can be great for Black & White photography as well as for capturing shapes and textures. You may need to work a little at it, but you can make great, unusual images at this time of day by learning to understand and use the characteristics of harsh light.

  • Twilight (Early in the morning or late in the afternoon) - the Sun is low in the sky:
    • Intensity: Which each second that the Sun rises and sets, its strength reduces therefore giving less and less light.
    • Quality: The Sun’s light is soft, producing evenly spread illumination with low contrast and smooth transitions.
    • Color: The Sun emits short wavelengths, giving warm color hues. As it travels through the atmosphere, the light bounces off dust, moisture and other particles causing different wavelengths to travel at different speeds thus giving off lots of color.
    • Direction: As the Sun is low in the sky, it comes in at an angle, producing long shadows.

 

Civil Twilight is an ideal time for urban, city and landscape photography. The artificial lights from various cityscapes start to appear and these can help create amazing images. The dim, low natural light allows shooting long exposures without the use of neutral density (ND) filters. If the sky is clear of weather and the moon is rising or setting, you might even be able to get it into your images.

 

The Golden Hour (when the Sun is rising) and the Blue Hour (when the Sun is setting) are ideal times for landscape and portrait photography. Light is soft, and the intensity is low with warm colors that are more pronounced. As the light is low, it may be a good time to include the Sun (during Golden Hour) or Moon (during Blue Hour) in your images.

 

As Astronomical Twilight approaches, the sky becomes darker. Star constellations become more visible and the time is right for night photography.  During night photography, you must consider the time and phase of the moon as it replaces the Sun in terms of emitting natural light (Moonlight instead of Sunlight). At the end of the Astronomical Twilight and during a New Moon, the completely darkened sky can be filled with Stars as well as other types of astronomical objects such as planets, galaxies, and nebulas.

 

A Final Word:

Although lighting is one of the most important factors on producing an amazing image, it is not the only factor. Other aspects such as composition, subject, exposure, focus, timing, tones of light and dark color, shapes, intent and inspiration all come into play. More about these at future HCC PMES sessions.

 


 


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