WORKOUT SESSION: MEET KELVIN

September 20, 2016  •  Leave a Comment

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I know this character who runs hot and cold, warm and gregarious one minute and cold as iced Alaska the next. He's a cool cat on a sizzling streak, a blues man with chili pepper licks. He dresses to the nines - emerald shoes, cerulean suit, tangerine tie, kaleidoscope eyes; his colors may complement or clash but are always bang on. He talks in symbols, rhymes in fractions, and glows in the dark. And those beguiling eyelashes.
 
His name is Kelvin.
 
You'd think with attributes like that, his name would be Rodrigo. Or Antony. Or even Richard (pronounced Ree-Shard). But nope, it's Kelvin.
 
Kelvin is Type A in the morning, Type B at beer o'clock, on the move, and rarely lives in the same location longer than breakfast. You might find him on the 3500 block on Sunset Strip (the seedy part) or dueling it out at 9800 Main at high noon in Tombstone, AZ. Kelvin hangs around galleries, art supply stores, and pro camera shops. He's a rapidfire talker, kind of a know-it-all, and can bore the socks off a sock puppet. But he does know his color theory.
 
Hold on... Kelvin just IM'd me. He noticed I was online talking about him. He can't stand that because, you know, he might be misquoted or something. "Please Don't Let Me Be Misunderstood" is his favorite song. It's even on his answering machine, like a sledgehammer upside the head. 
 
So pardon me, he wants to talk a bit. I'll record the conversation while you're waiting:
 
Kelvin: So you're trash-talking me again, then? You wanker. 
 
Me: Who, me? Would I do that?
 
K: Yeah, right? Like you know what I know. Not. 
 
M: Ok, then let me ask you this, genius. What's the big deal about cameras and color temperature? Why not just shoot WB Auto and let the camera figure it out?
 
K: Seriously? Let me explain so that even you can understand.
 
M: Alright. Thanks. I guess.
 
I erased the rest of the conversation because it went on for 40 minutes. Remember the sock puppet? That.
 
But here's the gist.
 
All color photos have to translate "temperature," or the color characteristics of visible light from infrared to ultraviolet, to something we can understand visually. Cameras have to deal with it first, and adjust ambient wavelength readings up or down until their little brains think it's comfortable to your eye, sort of like what you do with the furnace thermostat in your house. 68 degrees might be just right for you and too cold for your wife. Wife wins. The automatic features in a camera don't always get it right either, but that's what your white balance controls are trying to do.
 
Visible color temperature is measured on the Kelvin scale, pretty much the same way as Fahrenheit. Colors that read "warm," say reds and oranges, fall in the lower end of the K scale, down in the 3000 Kelvin (K) range. "Cool" temperatures, the blues and greens are up in the 7000 to 10000 K range. Overall color temperature is what gives a photograph its ambient feel, or mood. A "cool" blue river scene at dusk will feel more restful and serene than a "hot" fashion model in a red dress leaning against a pink Lamborghini, for example. [Fun fact: Ironically, we visually read the higher K numbers as "cooler" even though they are indeed "hotter." Go figure.].
 
Your camera comes with a dial for selecting "white balance" which is supposed to make white things look white. Our eye/brain system compensates automatically for a wide variety of lighting conditions, but a camera is much more basic. It's actually more accurate and truthful. So while a white dress lit by candlelight looks white to us, the camera will record the white dress as yellow. Auto White Balance kicks in and makes an internal adjustment to increase the ambient color temperature from say, 3000 K to 6000 K. In the "corrected" image, sure enough, the dress looks whiter. It's probably still not technically correct, however.
 
A camera's white balance selector has other options besides Auto, fortunately. You may have used some of the presets - tungsten, fluorescent, flash, sunny, cloudy. But we're going to ignore all of those for this assignment.
 
The white balance dial (or internal menu setting) has one marking with a K on it, and yes, it stands for Kelvin. Go there now. Why? Because chances are close to 100% you never have. Imagine the fun you'll have by setting a desired color temperature directly yourself. Set it to 3000 K and take some shots. Re-set it to 5500 K and take more shots. Set it to its highest value (perhaps 10000 K) and fire off one more series of shots. You should see a profound difference between each setting. One might look "accurate" while another looks "surreal." You can fine tune the K scale to either color correct an image or create an outlandish mood. It's your creative choice.
 
If you're catching on, you've probably figured out that there is a lot of room for subjectivity when dealing with color. And that's the point. Ask Van Gogh and Picasso to identify red and they'd probably end up in a spectacular paint-hurling bar fight that I'd pay to see. And neither would be "correct," of course. The purpose of this assignment is to relax the chains of color perfection and to enjoy playing with them for their own sake. Tell your critics that Kelvin said it was ok. 
 
So, if you want to make a bluesman blue, color temperature is the paintbrush you need. Set your white balance to K and krank the kontrols from krazy to kool.
 
Extra credit: If you shoot in raw, you can go one step better. You can change the color temperature of your photos after the fact because Lightroom and Photoshop have essentially the same color tools as your camera. In the Lightroom's Develop module, under Basic, slide the white balance Temp slider from one end to the other. You may notice that the scale is 1) reversed (cyan to yellow) and 2) incomplete (green to magenta appears under Tint); the tools are for correcting or compensating for color temperature, not setting it directly. 
 
Extra Extra  Credit: Color theory can be Alice's Rabbit Hole, endlessly fascinating and/or frustrating. There is a lot more to color theory than meets the colorblind eye. This assignment is not meant to take you there (we're not even scratching the surface of the surface), but if you'd like to take the red pill, I know a mad hatter named Leo... 
 
Some ideas for MEET KELVIN:
  • Adjust the K temperature in-camera, which will give the entire image a universal color cast. Try the lowest number, then increase in stages to the highest. How does the overall mood change?
  • Shoot an 18% gray card using different K settings. What happens?
  • Identify the "normal" Kelvin temperature range for the following: sunrise, noon, sunset, post-sunset, indoors under fluorescent lights, indoors under tungsten or LED lights.
  • Is outdoor noonday K different in summer than winter?
  • Google "Kelvin Color Temperature" for some great explanations and helpful charts for your explorations.
  • Don't forget to set your white balance selector to your desired default position (usually Auto) when you're done experimenting
 
Some sample previews for the upcoming Circle of Confusion sub-group:
  • In Lightroom, you can adjust color temperature for just part of the image. Make half the photo orange and the other blue using the gradient tool.
  • Use the Auto WB function in Lightroom to correct the color cast for each of your in-camera experiments. What happens to the K values for each? Try the eyedropper on the gray card. Any different?.
 
At some point, you'll start to predict what Kelvin temperature is best for a particular situation. You'll see light more like your camera and be able to adjust for it reliably. It can make for some weird overheard conversations like:
 
You: Hey, I found the best ambient 2750 K alleyway ever last night! Pure sodium vapor!
Them: Yeah? Where? Wanna meet there tonight? I'll bring my strobes and gel to 8000! Got some models?
 
And so on.
 
Happy shooting!
 
MEET KELVIN will run for two weeks, from September 21 through October 4.

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