Getting Skin Tones Right
Digital Portrait Techniques

Here is the image that I want to print: my kids goofing around in front of a skyscraper eerily reminiscent of the World Trade Center. While the image looks good I always refer to my reference image before printing.
Photos © 2001, Jay Abend, All Rights Reserved

While it's clear to every serious photographer that digital cameras will eventually replace film as we know it, there's still cause for concern with the skin tone of digital portraits.

Unless you use the $23,900 Foveon II camera, with its three independent 4 megapixel monochrome sensors, you're shooting portraits with a "Bayer Pattern Array" sensor. In other words, you're sampling small areas of the image in a dyed pattern of blue, red, and green. (Look closely at your TV set and you'll see a similar array.)

Technology right now must live with monochrome pixels that only see varying levels of brightness, not changes in color. Why does this matter? Mainly because the processing firmware in your camera goes through an elaborate set of calculations to try and "guess" what color was really on each space. Different schemes are used by different manufacturers, but in general all manufacturers must wrestle with issues like color aliasing, background noise, and overall color fidelity. Most images from modern digital cameras look pretty good, but a constant complaint from digicam shooters is the color balance of skin tones.

Skin Tone Reference
Unlike practically every other subject we shoot, everyone has a very concrete notion of what human skin looks like. The toughest skin color to accurately reproduce is the complicated peach-like coloring of Cau-casian skin. In fact, a nasty rumor circulated among the digicam cognoscenti that the major Japanese digicam manufacturers balanced their algorithms using Asian skin, which typically exhibits a more yellow cast than Caucasian skin. In addition, the major Japanese companies use plenty of different subjects to design their algorithms, and have learned that the subjective rendering of skin tones is just plain tough.

Wow, what a difference! The image corrected as explained in the text is really warm and colorful, with no trace of "digital" skin tones.

Among the pro-level SLR digital cameras, photographers report mixed results with Nikon, Canon, Kodak, and Fuji cameras. While the Kodak and Fuji have been heralded for their lifelike skin tones, Nikon and Canon owners have adopted workflows that allow them to produce skin tones that rival film. Many pro portrait shooters I speak with claim that their Nikon D1X and Canon 1D and D30 images rival the results they used to get on 120 color negative film.

What About Point-And-Shoot?
Even if you don't own a $3000-$6000 pro SLR you can produce really excellent portraits. Over the past three years I have owned several inexpensive point-and-shoot digicams, as well as Kodak and Canon SLRs, and I have produced portraits with each device that rival film. Sure, 8x10 prints from my Nikon 950 really can't hang with custom lab prints from a Hasselblad and Kodak VPS III film, but my D30 images are close. Things like background noise, sharpness, and color aliasing are all important aspects that make up a digital image, but the bottom line is that if your color is really good, usually the image is acceptable. That's right, even if your image is soft, the noise is noticeable and there are traces of digital artifacts, good color makes a print look "correct."

"Good" Color
What is good color and how do you get it? Well, of course, it is subjective, but once you see it you know it's right. Unfortunately for us, we're dealing with three distinct color spaces. There is the "real world," what your subject really looks like, your monitor color space, and your output device color space. Color management schemes like Apple's Colorsync do an excellent job of getting all three spaces into the same ballpark, but they are far from perfect. Calibrating your monitor and output device help, as does assigning a correct color profile to your camera.

This is the way you do it: open a tiny version of your reference file and a bigger window with the file you want to correct. Now I can see how pale the new image looks in comparison.

All of that stuff is a great way to get your digital imaging system tuned up, but I'm more from the old-fashioned trial and error school. To get your new technology to replicate the results you got from your old technology, you sometimes have to go backward.

Color Tests
I started with a regular old color print, a nice 8x10" headshot that exhibited a really great sense of color and overall tonality. I scanned it with my desktop scanner and then color corrected it so the on-screen image looked as close as possible to the print I was holding in my hand. Then I sent the print to my ink jet printer and experimented with the color settings until the ink jet print looked very close to the original. Finally, I sent the file to my favorite online print service, and once that print came back I was able to find a color output profile that sort of matched. Bottom line is, I was able to roughly close the loop--from start to finish all of my color settings basically agreed.

Now that I knew that I had some sort of reasonable "seat of the pants" color management system, I had to train my own eye to work digitally. While the best digital cameras produce results that rival the best film scans, the old-fashioned way of shooting color negative film and optically producing a type "C" print with an enlarger (remember those?) still reigns as the best way to take the expanded dynamic range of real life and put it on paper.

Here is my reference file. The model here has smooth clear skin similar to my daughter's, so I figured that it would be a good reference image.

Lighting Considerations
To replicate the look and feel of film I found that I needed to shoot with a smoother, lower contrast lighting style than I might have originally chosen for negative film. Of course every different camera has its own unique look and feel, but I find that I need to preserve my shadows and highlights. In other words, I don't want to either blowout my highlights or create rich black shadows. I want it smooth and even, with readable detail everywhere. It's so easy to jack up the contrast digitally, and the numerous steps taken from shoot to print usually add some contrast anyway.

In cases where I might have chosen a punchy silver umbrella I'll instead shoot through a big 42" white umbrella. Where I might have chosen a focusing spotlight for a hairlight now I'll choose a Chimera strip light. I try and keep everything punchy, but softer than I might have with film. You guys with fancy digicams and no real lighting might want to think about a small invesment. I've corresponded with dozens of Nikon D1, Canon D30, and Olympus E-10 and 20 owners who rely exclusively on the sun and a dedicated on-camera flash for their lighting. You'd be surprised at how many Canon D30 owners think a 550EX on-camera flash unit is a studio flash system! In fact, a surprising number of pro portrait photographers use mostly on-camera flash with a couple of small monolights in the studio.

I think that any serious photographer needs a lighting setup, one that is efficient enough to get a decent f/stop and versatile enough to handle reflectors, barn doors, umbrellas, and softboxes. (Strobes, in other words.) Since these cameras use very small chips and have adjustable ISO settings you don't need a big bear of a lighting system. I've been using a couple of sub-$200 AlienBees B400 monolights with umbrellas with my Nikon 995 and have gotten really outstanding results. In fact, my bigger and fancier Balcar studio strobes just plain pack too much power.

For sharper, more contrasty images I used this test image, shot using a tungsten Fresnel light.

Image Tonality
Once you have your system set up and you've got a way to light your subject you need to get a relatively objective way to determine your overall image tonality. While there are any number of ways to shoot test charts and the like to determine color balance, I find the only way is to "tune" my eyes to that acceptable test image of skin tone, and then use those eyes to dial in the correct color on the image I'm working on.

Here's how I do it. I have about one dozen images that I have found to exhibit really excellent color. You know, those pictures where the people really seem to leap off the print at you. I took each of these large 9-20MB files and downsampled them in Photoshop to very small 100k JPEG files. This way I can store 10 on a simple floppy disk and always have my reference skin tones with me. When I begin to work on a new image and my intention is to create a print either on an Epson printer or via an online photo printer, I'll try to figure out which of my reference images has similar lighting and contrast. I'll open the test image along with the new one and keep it open on the screen. First thing I'll do is to use the eyedropper tool in Photoshop to sample a range of skin tones on the test image, then sample similar areas on the new image. This should give me a pretty good idea.

Get Info
For example, my best test shot exhibits really gorgeous color, shot with a Canon D30 and color balanced for my client. When I sample the model's skin I find light skin around 254 Red, 209 Green, and 183 Blue. (If you open your photo-editing program and create a new color swatch with those numbers you'll see what I mean.) Dark skin looks like 181 Red, 113 Green, and 67 Blue. When I open the image that I'm editing it looks pretty good to my untrained eye. Once I open the test file and compare them side by side I can see the skin tones look very, very cool and pale. My light skin is 202 Red, 161 Green, and 136 Blue. Obviously I need to get some more red into the image, and deal with the greenish cast. I use several tools, but for this image I chose color balance, hue and saturation.

For commercial shoots shot in daylight with studio strobe I always refer to this test image, which adequately displays the desired color balance when using this technique.

My technique for pale images starts with a shift toward warm. I'll dial the Hue control -5. This shifts everything toward magenta. While it may make my skin tones too pink, it gets me started in the right direction. Next I'll go to color balance and dial in a touch of red in the shadows, a little bit more in the mid tones and a bunch in the highlights. I'll then add some yellow--usually mid tones only. This will shift the skin back toward the orangish/peach-colored Caucasian skin. My next trick is to saturate the Red channel only about 10 percent, then saturate the entire image another 8-10 percent. Lastly I have increased the blue of the sky to create more contrast. The results are quite startling! The original file that looked halfway decent (and would have probably be printed as-is by many) looks incredibly pale, with a blue/green overall color balance. The corrected file has that rich, warm "Velvia" look with warm and balanced skin tones.

The key element here is the existence of a known reference file. Without something to "calibrate" your eye before every image-editing session you'll invariably create results that are terribly inconsistent.

I have not found any automated image correction system that can rival the results I get from using my own artistic eye, a good monitor, and some patience. Using the test image really makes small things like monitor color shift less of an issue, since you're matching a file that is also displayed using the same device. The image I corrected here was output to both an Epson ink jet and to a Lightjet 5000 photo printer. Both prints look really smooth and absolutely "film-like," which is the whole idea, right?

Adobe Systems Inc.
(408) 536-6000
fax: (408) 537-4031

AlienBees Inc.
(877) 714-3381

Apple Computer, Inc.
(800) 767-2775

Calumet Photographic Products (Balcar)
(630) 860-7447
fax: (800) 577-3686

Canon U.S.A., Inc.
(516) 328-5000

(303) 444-8000
fax: (303) 444-8303

Eastman Kodak Company
(716) 724-4373
fax: (716) 781-1730

Epson America Inc.
(562) 981-3840

Fuji Photo Film USA Inc.
(914) 789-8100
fax: (914) 789-8656

Nikon Inc.
(631) 547-8500
fax: (631) 547-8518

Olympus America Inc.
(631) 844-5321
fax: (631) 844-5262