Welcome to week three of my four part learning series on light. This series covers the basics of light and how it relates to your photography. As photographers, we are concerned with four attributes of light, Quantity, Quality, Color and Direction. This week we will focus primarily on the third important attribute of light – color. As with any physical theory, I invite you to take the time to research further, this article represents my stance on color of light. Now that the public service announcement is out of the way, lets go…
Whether you are a stills shooter or dabble more in the video side of imagery, understanding the basics of light color, or temperature can have a significant impact on your photos or videos. Color temperature is generally expressed in Kelvin, using the symbol K, a unit of measure for temperature based on the Kelvin scale. The Kelvin scale usually gives a numeric value to a color of light. Temperatures over 5000 K are called cool colors (bluish white), while lower color temperatures (2700–3000 K) are commonly considered warm colors (yellowish white through red). This is what we as photographers consider the White Balance (WB) of a photograph. I am sure at one time you shot a picture in your living room with incandescent light and everything looked orange or yellow, or maybe you shot a photo in the snow and everything came out blue rather than white. The reason for this is your camera’s ability to evaluate the scene you are shooting and its effort to bring the overall color of your image toward an average or middle grey. Whether you shoot with a point and shoot or a $10,000 DSLR, this can be a problem. We will discuss how to resolve this issue but for now, let’s look at a couple examples of White Balance.
I did a quick google images search for white balance and found some good examples that illustrate how color temperature can affect the scene you are shooting. The first image shows what we were just talking about, the orange yellow tint of an image shot indoors with light sources of different color temperature. So, now that you can see the difference that light temperature can make in your image, you might be asking how it can be fixed. Whether you use a free solution like Gimp or Adobe’s Lightroom, there is an option to change your white balance. Generally, you have two options, one where you select an eyedropper and click a middle grey color in your image, or a slider for more manual adjustment. Since we are all shooting in RAW (right?) you have a lot more flexibility in changing your white balance after the fact if you forget to set it when you are taking your photos. I see white balance as just one more aspect of creativity in fine tuning or processing your images. While I (generally) choose what would be the proper color temperature for an image, I am certainly not a purist, and often find myself happy with an image warmed up a bit. In the image shown I chose a final white balance of 5500K which warmed up the image significantly and made the orange rocks of the Garden of the Gods pop a bit more even though it was shot in the middle of the day.
The biggest consideration when discussing color as it relates to photography, is how you can be sure you are seeing the color I am seeing. The importance of a properly calibrated monitor cannot be overstated. I personally know photographers who shoot with what I would consider expensive cameras (Canon 1d series) which cost well over $6000, but rely on a monitor that has the brightness turned down a bit for image processing. It boggles my mind to think that someone would spend a lot of money on a camera and not another 100 dollars for even a basic monitor calibration device. I have personally owned both the ColorMunki and Datacolor monitor calibration devices and find both to be more than adequate for ensuring that you are working in as accurate colors as possible. The takeaway here should be – if you don’t have a monitor calibration device, get one.
Your color space is also important especially when planning to post images to the web. sRGB, Adobe1998 and ProPhoto RGB are the main three color spaces most work in. So what is a color space? A color space is a set of colors, the wider the space the more colors that can be displayed. This is however limited to the display device. sRBG is an earlier, smaller set of colors and is a good baseline of colors to use when uploading an image to the web. Using sRGB ensures that the bulk of the devices that will be viewing your content online will see an accurate representation of the colors you have chosen. Adobe1998 was created by Adobe in 1998 as a set of colors that closely represent the colors capable of being printed by typical (not high color) CMYK printers. So if you plan to print, less conversion is required by your computer before sending the image to your printer. I consider this a medium all around color space and find that images in this space come out more color accurate when printed. ProPhotoRGB is the widest color space of the three in that it is capable of showing 100% of all likely surface colors. Again, this is dependent on the quality of your monitor. Which do I use? I edit in ProPhotoRGB, convert to Adobe1998 before I print and convert to sRGB if I am posting to Facebook or other web site. If you take the time to convert before you upload or send to your printer, you have more control over the final look of your image, and if you are printing, can save yourself money be ensuring the colors are what you are expecting before you push that print button.
We got off the topic a bit discussing color space, but in the end it is all related. Understanding how the color of the light on your scene affects your image is equally important to the basic knowledge required for delivering accurate colors to your viewers. I hope this introduction helped you out, and answered more questions than it created.
Get out there and take some pictures!