Photography 101: A Primer on Color Photography, Part I
Our next stop in our Photography 101 series focuses on yet another essential element of photography: color. In this two-part post, talented WordPress.com photographer, Ming Gullo of A View with Ming, introduces us to the fundamentals of color, from temperature and white balance to hue, saturation, lightness, and contrast. The images on her blog, and below, are vibrant and stunning. Enjoy!
How a camera looks at color
To understand how our cameras recognize colors, let’s first talk about how our eyes recognize colors.
As you may know, white light consists of many different color lights with different wavelengths. For example, we see a red apple. The reason why it’s red is because the surface of the apple reflects the wavelength of red light into our eyes. At the same time, the apple’s surface absorbs the rest of the color lights, so we see the apple only as red.
Our eyes have three different sets of nerves to recognize three primary colors: red, green, and blue (or the RGB spectrum). These three colors can be mixed together in different variants to produce different colors. So, let’s say we’re looking at a flower. If the surface of the flower reflects more blue light, a little bit of red light, and no green light, we will see a purple flower (or close to purple, depending on the ratio). When an object reflects the three primary colors in the same ratio, we’ll see this object as white.
Camera films and digital camera sensors recognize colors in a similar way. Here, I’ll focus on digital cameras since they’re commonly used among many of you. Digital camera sensors consist of pixels, which collect photons (energy of light) when the shutter is pressed. To be more accurate, instead of saying “collecting photons,” let’s say “capturing the intensity of photons.” More photons means the pixels are brighter, and vice versa.
So, if all we’re measuring is brightness and darkness, how do we get color? That’s why our digital cameras have filters. A filter works in the same way our eyes work — filtering red, green, and blue. The filter causes pixels to register photon intensities for one of the three colors, and once the full image is captured, it is digitized into an output like RAW, JPEG, or TIFF, which we’ll cover later, in part two.
Color temperature and white balance
Understanding color temperature is crucial in photography, and visual fields in general. In simple terms, each light source has its own individual color. Indoor light sources, such as candles and tungsten bulbs, give off light that’s close to red. Some outdoor lighting, such as sunsets, also looks reddish. These light sources give photos “warm” looks. On the other hand, daylight gives off a “cool” bluish light.
Here’s a set of macro droplet shots captured in a controlled environment. The light sources are a couple of sets of compact fluorescent lights (CFL). At a glance, you can see how the shot varies in three different settings:
This first photo, which I shot using the camera’s automatic white balance (WB) setting, has a very warm tone:
I shot this second photo using the camera’s fluorescent preset, in which the camera applied its best guess corrections:
Finally, the third image uses manual WB settings, which is adapted for the white CFLs I used:
A closer look at temperature and white balance
To understand how we achieved these different images, let’s talk more about color temperature. Color temperature is stated in Kelvin (K) — if you’re curious, take a peek at the color temperature chart below on the right.
When I try to capture accurate colors, I take color temperature into account and set the camera’s white balance based on my experience with familiar light sources (or using the camera’s own smarts). Digital cameras usually provide a number of color temperature presets, such as Tungsten, Daylight, Cloudy, and Shade.
If you’re not picky about being accurate — since the preference of color is highly subjective — 8 out of 10 times your camera presets do a pretty good job. However, fluorescent bulbs usually don’t provide consistent color of light, and since compact fluorescent lights (CFLs) emit light from chemical reaction instead of heat, it’s more confusing when you’re trying to figure out the color temperature.
Luckily, vendors like GE and Sylvania usually provide a figure known as Color Rendering Index, which measures how accurately a light source represents standard color. A bright white CFL usually measures from 3500 to 4100 Kelvin (K), warm/soft white CFL usually measures from 2700K to 3000K, and an average daylight may range from 5500K to 6500K. That said, the shot #2 above appears a little too “cool” for me — it didn’t accurately capture the daisy’s powder pink color.
Shooting outside in daylight
Most of us take photos under daylight. Daylight is produced by the sun — and so is moonlight. Daylight is visible even when we can’t see the sun! So, the color temperature of daylight can vary greatly. When sunlight is direct, it can be bright and harsh. The color temperature of a sun-filled noon may be 6500K. At other times of the day, when the sun is not as high, the color temperature on average is around 5500K. During golden hours (the one hour before dusk and after sunrise that Wenjie mentioned in a previous post on light), the color temperature of daylight may dip as low as 2000K.
Capturing a satisfactory moment requires dedication and patience. I shot this halo photo during one of the coldest days of winter, on the south shore on Long Island, New York. If you know the geography of Long Island, you know most of the shoreline doesn’t face east or west. I’d been trying to scout a sunset location for a while until I found a west-facing marshland on Long Island’s south shore. Beyond the marsh, there is a wide-enough waterway where nothing blocks the sun. The best sunset here, from my experience, is in January and February.
That day, I got there around 5 pm, walked about a mile in 4 ºF (-15 ºC) wind chill to reach my location, and waited. I’m happy with how the wind-swept reed came out! I also got some additional rewards on the way:
An assignment from The Daily Post editors:
Phew! Ming has introduced a lot in this post about color, temperature, and the settings that affect our shots. If you’re up for it, let’s experiment! We can start simple:
- Choose an object and shoot it indoors under a light bulb. Then, photograph it under a different light source. Notice any differences?
- Drag a photo into an easy-to-use photo editor like PicMonkey and click on the Colors tab to adjust the “temperature” setting. What happens to the image? What type of temperature do you prefer? (You can also experiment in your software or editor of choice, like Photoshop, Picasa, or something similar.)
In part two, we’ll take a look at hue, saturation, lightness, and contrast, which some of you may already know about. Ming will also share more of her colorful photography — check in tomorrow!
About Ming Gullo
I’ve been always a lover of art. I went through formal training of painting and illustration when I was younger, where I learned the basics of art. Over the years, I’ve been a freelance children’s book illustrator, graphic designer, and web designer/programmer. For me, photography is a perfect marriage of art and technology, which satisfies both sides of my mind. Currently, I’m based on Long Island, New York. You can see my work on Facebook, 500px, and WordPress.com. You can also find my work in magazines — such as Photography Masterclass and N-Photo – or on Nikon Germany’s Facebook page.
Previous posts in the Photography 101 series
- Philosophy of Photography
- Viewing the World with a Photographer’s Eye, I
- Viewing the World with a Photographer’s Eye, II
- The Fundamentals of Light
- The Quality of Light
- The Rules and Elements of Composition
- Finding the Best Shot — Portrait or Landscape?
- Finding Your Focus
- Establishing a Point of View
- Shape, Line, Texture, and Pattern