Skin Tone, White Balance, Etc Part II

In part I of this series I discussed a bit of generalizations about white balance and skin tone. One of the things that I brought up was scene context and how that might influence what kind of color rendering you might want. I hope I also demonstrated that in many (most) non-studio situations you are always going to have more than one color of light influencing your subject and your scene. The picture I used to illustrate the second point didn't have much context to see. The differences in light source colors were all based on seeing the skin. Sometimes judging that from only the skin is difficult if your not really used to looking at it. Today I'll continue with another shot from that same scene but this time with a bunch of context.

For consistency I'll continue using Aperture 3's white balance adjustment in skin tone mode. Let's take a look at the screen shot below (open it in a new window or download it for a full size view). Three different color renditions of the shot. Starting from the left and going right we have the coolest to the warmest. My personal preference is the one in the middle. Not due to the fact that it's middle of the road, it's the one that I choose. The color rendition to either side is skewed a bit cooler and a bit warmer from that point.

To get to the one in the middle I sampled a bit of skin that was facing the camera. This gave me a neutral rendition which I ticked a hair warmer using the white balance warmth slider. No matter where you sample the warmth slider always starts at 0.50 and has a range from 0 to 1.0. The version in the center happens to be at 0.61, a tiny bit warmer than my sample. The version to the left of center is 0.20 cooler. The version to the right of center is 0.20 warmer. I could go with either of the warmer versions in this scene. Too subtle a difference? Not really. In the range of normal these are the kinds of variations appropriate. Okay maybe they are too subtle for illustration so let's look at this with a wider variance.

How's that? Now it's not subtle at all but it's also not so far off it look horrid. Same as at the top – same skin sample but the one in the middle is at the default 0.50, the left is 0, and the right is at 1.0. These are the absolute largest variations within that sample from coolest to warmest. Maybe this is a good way to start your evaluation if you're not so sure where you want to go? Sometimes it's helpful to make three different versions and look at them side by side as I'm doing here.

Let's revisit that context thing for a moment now that we have a bunch of scene context in this image. The light falling on Mary is mostly soft window light which I tend to prefer a little on the cool side. Here I actually prefer the warmer renditions due to the context of what is obviously direct sunlight streaming into the room and bouncing around. It just feels more right. I don't know if I would go all the way crazy warm like the version above on the right. I do know I would prefer something in between the middle image and the one on the right. Exactly where I ended up when doing a quick and dirty correction on this particular image.

There's also a few other things to point out now that we can see some scene context. Things that you could see the results of with various skin tone samples in part I but might have been hard to see directly are now clearly visible. I'm talking about the actual color of various light sources in the scene. Let's go through them real quick.

  • See that blue through the glass on the right edge of the frame. It's clearly blue. It's sky light without any sun coming in a far window in the background. It's far from neutral. You would be surprised but that matters for context. I made a bunch of images that played off these blues compared to the far warmer light in the room Mary and I were in. You can even see all those blues in the background in part I against the skin. Just as important is what you couldn't see in those images - you could not see the the actual sunlight nor it's context.
  • That maybe a bit esoteric so let's look at something that is front and center the direct color influences on the black leggings that Mary's wearing. This is easy to see and stands out. It's very noticeable even looking at it in real life. Take a look at any of the center or warmer renditions, it's easier to see. Look at the highlights on the black. You brain knows it's the same black but the highlights range from blue to orange. The blue ones are from the sky light coming through the window the orange ones are from the sun bouncing off warm wood and back onto Mary. These differences look okay, actually attractive due to the scene context.

Remember the hair color trick I mentioned last time? I find it easy to remember basic hair color in relative terms and can use it after the fact as a guide in rendering color within some normal range assuming I don't want an effect. I happen to notice this in people but for those of you that don't I'll make it more specific. Most people's hair no matter if it's brown or blonde either skews towards yellow or towards red underneath the brownness or blondness. If what's going on in your picture is going in the opposite direction of that then you are in the wrong ballpark with respect to color unless you want some effect. As with most effects it might be better to go really far rather than just a little "wrong". If you are going for a more natural rendering it's definitely not a great idea for the underlying red/yellow tendency in someone's hair to be opposite of what it is in real life.

Mary's hair does not skew towards red at all, it's mid to light brown and skews more toward yellow. Take a look at it in all these variations. I can live with it a hair warmer due to the scene context. Without that I tend to prefer a more neutral rendition. While we're looking at the hair take note of what's going on with the hair at the back of Mary's head. No matter what the overall color treatment there's a warm orange glow there. It's from sun hitting the dark warm wood on the door right behind that spot and bouncing back.

I bring these things up for two reasons. First – it's part of the topic at hand – scene context. The second reason is noticing these things when you are shooting – specifically looking for them is a good idea. They can make or break a shot. If you get some stuff going on like that because you're wearing a vivid blue shirt and standing in the sun bouncing that blue into your scene and onto your pristine white linen dress it will probably ruin the pictures. In other cases stuff like that can really make a picture sing. Typically if it's a stronger colored reflection scene context is key to making it work.

One last thing before I close this out. Take a look at the saturation of the skin from cool to warm. Hmmm cool is less saturated and warm is more saturated. I'll give some thoughts to this in part III.


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