The post How to Understand Light and Color to Improve your Photography appeared first on Digital Photography School. It was authored by Rick Ohnsman.
The morning sun shone through my kitchen window, catching the vase with a rose in it on the window sill. A low cross-light highlighted the texture on the rose, while the purple glass vase cast a pattern of colored light across the counter. The photographer in me studied the light, saw the potential for a photo, and went to get the camera.
From observing the sun shining through a vase on the window sill to the finished image, this idea started with simply seeing the light.
A simple observation of light. That’s how a photo can start – learning to really see the light. Understanding its properties, knowing how to control and shape it – those are the things that will take you from a casual snapshooter to a creative photographer. It’s a matter of crafting photographs rather than simply taking snapshots.
George Eastman helped bring photography to the masses with his development of roll film, simple cameras, and readily available processing. You’ve certainly heard of the company he founded – The Eastman Kodak Company. Eastman understood the importance of seeing the light.
He put it like this:
“Light makes photography. Embrace light. Admire it. Love it. But above all, know light. Know it for all you are worth, and you will know the key to photography.” – George Eastman
The vase set-up led to experiments with glasses, colored water, and more exploration of light.
Harnessing the light
The rest of the photo session explored the interplay of light, color, shadow, texture, shape, and pattern. From shots of the glass vase and rose, I switched to glasses and vases filled with water dyed with food coloring. I experimented with different camera angles, positioning of the subjects, and different background objects. I shaped the light with cardboard “flags” and the Venetian blinds through which the sun was streaming to allow different looks.
The low angle of light also provided ways to cast shadows and projections of color.
In this case, the light source was simply the early morning sun. I could have created other effects had I used artificial lights, say a snooted Speedlight to cast a beam of light right where I wanted it.
Studio photographers become masters of light manipulation by using their knowledge and a variety of lights and light modifiers. Their skills draw upon understanding the properties of light and how to harness it.
Landscape photographers may not be able to create their own light, but they also understand its properties. They know when, where, and how to make the most of the light presented to create the look they seek.
Light Physics – the properties of light
You need not become a physicist to be a photographer, but a little understanding of the properties of light can be beneficial to your work. So, a little science knowledge can help your art. Left-brain, right-brain – good photographers use both sides.
What is light?
Light is photons of energy. It has both wave and particle properties.
Electromagnetic spectrum
Human eyes can only see a very tiny portion of what is called the Electromagnetic Spectrum. Some photographers use Infrared photography to go a little further past the red end of the visible spectrum, and ultraviolet light sources can take us a bit further past the violet end. Specialized cameras can also capture X-rays.
Human eyes see only a tiny portion of the Electromagnetic Spectrum, that portion we call Visible Light.
(transferred by Penubag (talk · contribs) on 05:04, 15 May 2008 [CC BY-SA 2.5 (https://creativecommons.org/licenses/by-sa/2.5)]
Properties of light
When speaking of light, we often refer to its properties. These are:
Quantity – (Also called Intensity or “Brightness”)
Quality – Photographers will use the terms “Hard” or “Soft” light.
Technically, these refer to the shadows cast, not the light itself. The hard or softness of a shadow (a place where the light is blocked), depends on the size of the light source relative to the subject. Thus the sun, which is, in reality, huge, can cast harsh shadows (hard light). This is because as a pinpoint of light in the sky, its relative size to the subject is small.
On an overcast day, the whole sky may be the light source – nature’s giant softbox – and the shadows are soft or non-existent.
Direction – Light waves travel in straight lines. They can be redirected however through Reflection or Refraction.
Reflection – Light hitting an object can bounce off that object. In fact, anything we see is a result of light bouncing off that object. The apparent Color of an object is due to what colors (wavelengths) are absorbed versus those reflecting. A red apple is that color because it absorbs all other colors in the spectrum and reflects only the red wavelengths.
With highly reflective objects, the angle the light hits an object will be the same angle it is reflected. The angle of incidence = the angle of reflection.
Refraction – Light can pass through some objects and be refracted or redirected. Put a pencil in a half-full glass of water, and you will see how the light is refracted differently as it passes through the air versus the water and the glass. Camera lenses shape light through refraction. The image projected on the camera sensor is actually inverted. It is the same as it was when view-camera photographers threw a cape over their heads to see the image on a ground glass before making their photo.
Dewdrops act as tiny lenses refracting the light passing through them.
Light waves can:
Pass through transparent or translucent objects.
Transparent objects – little if any light is scattered as the light waves pass through – i.e window glass.
Translucent objects – Some light passes through the object but waves are scattered and objects on the far side are not clearly visible.
Reflect or bounce off an object – We call highly reflective objects “shiny.” They will often produce Specular highlights. Objects which break up and bounce light in many directions have a matte quality and Diffuse the light.
Be scattered – Light waves are bounced in different directions
Be absorbed – As discussed, objects have color because they absorb some (colors) wavelengths and reflect others. Because light has energy, the more light energy an object absorbs the warmer it will be. This is the reason black, (which absorbs most of the light energy), warms faster than does white, which reflects most of the light.
Be refracted (bent) as light passes through. Denser objects refract light more (pencil in a glass of water shows example air vs water vs glass). Diamonds have a very high “index of refraction” and thus are sparkly.
Shadows – Shadows are formed where light is blocked. Photographers seeking to understand light can learn much by studying shadows as they will give clues to the other qualities of the light.
This abstract image is all about the light and shadows
Dispersion – Visible light can be separated into its component colors due to different degrees of refraction through an object. (This is how prisms work and how rainbows are formed)
A rainbow is an example of white visible light being split into its component colors when the raindrops refract the light and disperse it.
The Speed of Light – Light travels faster than sound at approximately 186,000 miles per second (300,000 km/s). Sunlight takes 8 minutes, 20 seconds to reach us. From the next nearest star, Alpha Centauri, light takes 4 years to reach us. At night we see the light from stars that took hundreds of thousands of years to reach us. Currently, the most distant star observed by astronomers is over 9 billion light-years away.
Photography and light
We know that without light there is no photography. Building on the basics of light physics, we photographers have further ways to define light and how we use it.
Photography and color
General photography works within the visible light spectrum. We use the Kelvin temperature scale to describe the color of light. For example, a candle’s flame is 1,200K, which is towards the red-orange end of the scale, and a cloudless day is 10,000K, which is at the blue end.
White balance
The human brain is good at correcting colors under different light so that we usually see “correct” colors. Cameras need some help. Using White Balance, we can index the color we want to be white or neutral in color, and all other colors in the scene will use that as a reference and adjust accordingly. Thus images shot in daylight, with flash, or under tungsten or fluorescent lights can all be adjusted for “correct” color.
A huge advantage of saving images in the Raw format is you can correct this later when editing. Unfortunately, .jpg images lock the white balance in during the capture.
The color of old tungsten light is quite warm, about 3200K on the Kelvin scale. This could have been white-balanced to be more neutral, but for this image, the warm light added to the antique look desired.
With light, all colors combined equal white. With ink, all colors combined equal black.
Color models
RGB
Your camera can interpret the world of color and reproduce it on a color monitor, but in reality, it really only “sees” three colors, Red, Green, and Blue (RGB). All other colors are created from these three. Use a magnifying glass to see the pixels on your monitor, and those are the only colors you will see.
Your camera sensor can also only capture those three colors.
If all three of those colors or light combine at full intensity, the result would be pure white. Because colors record by adding one to another, the term “Additive” is used.
Any of over 16 million colors can be defined using the RGB model, which has 255 steps of each color. So, white would be 255, 255, 255. Black is no light and therefore has an RGB value of 0, 0, 0. Pure red would be 255, 0, 0. A mixed color like pure yellow is 255, 255, 0, and something like a deep purple shade might be 113, 58, 210.
Pure Red is a primary color in the RGB (Light) model with an RGB value of 255,0,0 but in the CMYK (Ink) model it’s a mixture of Yellow and Magenta.
CMYK
The RGB model works fine in cameras and monitors where we add light to the blackness to create color. When printing, however, we are starting with a white piece of paper and subtracting from that white to create color.
Instead of red, green, and blue being the primary colors, printers use Cyan, Magenta, Yellow, and Black (CMYK) to create all other colors. (“K” is used for Black because it is the last letter of the word and not used by any other color, i.e. (B)lue). To save costs on ink, and to produce deeper black tones, unsaturated and dark colors are produced by adding black ink instead of just the combination of cyan, magenta, and yellow. So, while in the RGB model, pure red is defined as 255, 0, 0 the same exact color in the ink printing world of CMYK is something like 0, 100, 100, 0.
So as not to make your head hurt any further, I will not get into the complexities of color spaces, printer profiles, gamut and how we can be sure what we saw is what the camera captures and finally appears on a print. That’s a whole other and a quite complex subject. For now, know it is a lot of science and a perhaps a touch of magic.
Instead, you can read more about those topics here:
- Color Management Can Be Easy
- How to Prepare Images For Publication – Part One
How photographers control light
As photographers, especially in studio photo work, we have the tools and the means to control the light.
Here are the basic things we can do:
Transmit – Using lights of various kinds we can transmit light onto our subjects. We control the quantity, direction, and color of the light source. By changing the relative size of the light source to the subject, we can also control the hardness/softness of shadows.
Reflect – All objects reflect light to varying degrees (which is why we and the camera can see them). How that reflected light plays off of objects, or how we might use other objects, (reflectors) to bounce light into a scene is one way we shape and control the light.
Many of the principles of light discussed in this article are present in this shot. Can you identify them?
Diffuse –We can cause the light emitting from the source to scatter to varying degrees, (diffused), by shining it through translucent materials. This how softboxes and other light modifiers work.
Block – As light travels in a straight line, anything between the source and the subject blocks the light and creates a shadow. How and where we create shadows is as important as where we allow light to cast. Photographers use things like Flags, Gobos, and Cookies to cast and control shadows. An example, a “barn door” on a lighting instrument is a type of flag.
This image is all about the light. The backlit leaves are translucent and pass a portion of the light striking them, filtering out some colors and passing the golden parts of the spectrum through them.
When nature lights the scene – Landscapes – Landscape photographers and those using only natural light sources don’t have the same controls over the light, but they still need to understand it to become master photographers.
Learning how light works, how direct sun, diffuse light, time of day, season, angle, diffusing factors like fog, smoke, rain, and other “atmospherics” affect the image are all a huge part of becoming a student of light. A skilled studio photographer can create light. A skilled landscape photographer knows when and where to be and then very often, simply “waits for the light.”
A smoky sky filters out many of the colors of the light and passes the warm yellow and red tones. The side of the wheat facing the camera receives no light and so is silhouetted against the sun. Learning to see the light is key to becoming a good photographer.
Becoming a student of light
Sure, you can just get out some glassware, fill it with colored water, place it in the sun and make some pretty pictures. I encourage you to do that. It’s fun and you will likely make some nice images. You need not know the physics and terminology to make nice photos. But I encourage you to take it a step further. Use it as an exercise to further your understanding and become a trained observer of light because I really believe George Eastman had it right –
Know light. Know it for all you are worth, and you will know the key to photography.
The post How to Understand Light and Color to Improve your Photography appeared first on Digital Photography School. It was authored by Rick Ohnsman.
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