139. Lighten a Subject on a Snowy Background
Before You Begin
136 About an Images Histogram
138 Improve a Dull, Flat Photo
137 Improve Brightness and Contrast
Typically, the sheer brightness of snow changes the way your camera handles light from darker objectsand on a snowy day, almost everything is darker than snow. Digital cameras are especially sensitive to bright light reflecting off snow, bleaching out the rest of the scene and causing subjects in the foreground, including people, to appear muted and dark. Furthermore, because many digital cameras tend to normalize their light input on-the-fly, even though the snow is the brightest thing in the image, the camera makes it gray, making your foreground subjects even darker to compensate.
In remedying an image that suffers from this problem, you could start by invoking the Levels command, but you know already that your bright whites are already going to command the right edge of the graph for the RGB channel. Besides, you might not want to change your snow at all, especially if it's bright enough. The technique you're about to see helps you easily separate your foreground subject from your background snow (which is, after all, mostly the same shade), so that you can restore the foreground despite the snow.
Duplicate the Background Layer
Open the image you want to adjust in the Editor in Standard Edit mode and save it in Photoshop (*.psd) format. To display the Histogram palette if it is not already showing, select Window, Histogram. From the Channel drop-down list, choose Luminosity.
In the Layers palette, choose the Background layer. From the menu bar, select Layer, Duplicate Layer. Name the new layer Threshold.
Blacken the Subject Using Threshold
With the Threshold layer chosen, from the menu bar, select Filter, Adjustments, Threshold. In the Threshold dialog box, adjust the Threshold Level setting until the black area just covers your subject. You'll probably also blacken some of the shadows your subject is casting on the snow; don't worry, that's okay. Click OK.
Remove Holes from the Selection
Your subject should now be black and the background white, but that's only temporary. At this moment, your selection probably includes some specks of snow on your subjectespecially if she's recently been in a snowball fight. These beads of snow will produce holes in your black subject area. The simplest way to remove them is using the Brush tool. In the Toolbox, click the Brush tool, and then click the Default Colors button in-between the foreground color and background color boxes. Choose a five-pixel-wide brush tip from the Options bar and apply that brush tip to the small holes in the black image. Choose a larger brush tip and sweep away the larger areas of dustier snow from the subject.
Select the Subject
From the Toolbox, click the Magic Wand tool. In the image, use the tool to select the subject. In this example, the selection included the girl, the big stick she was holding, and a portion of the shadow behind her back. It did not include the shadow of the air conditioning unit in the upper-left corner. Use of the Magic Wand tool is explained in 76 Select Areas of Similar Color.
Convert Selection to a Layer
In the Layers palette, change to the Background layer, and select Layer, New, Layer via Copy from the menu bar. Name this new layer Subject. Your subject is now isolated on its own layer, where you can make adjustments that bring out its own details without disturbing the snowy background. You can also adjust the snowy background by brightening it significantly, without in turn over-brightening the subject.
You no longer need the Threshold layer. In the Layers palette, choose the Threshold layer and select Layer, Delete Layer from the menu bar. Click Yes to confirm. For now, your image looks exactly as it did before.
Adjust the Subject Layer
In the Layers palette, choose the Subject layer. From the menu bar, select Enhance, Adjust Lighting, Shadows/Highlights. The Shadows/Highlights dialog box appears. You might have to reposition it to get a clear view of both your image and the Histogram palette.
With the Histogram palette open and visible, it's easy to get a clear read of what the Shadows/Highlights command does, and what your limits are with regard to safely using it. Sliding the Lighten Shadows setting forward clearly bunches up the histogram from the left side against the right edge. You gain brightness, but at the expense of contrast, so be careful not to trade off too much. Similarly, sliding the Darken Highlights setting forward bunches up the histogram from the right side against the left edge.
Sliding the Midtone Contrast to the left bunches up tones in the histogram toward the middle of the chart, whereas sliding it to the right splits tones into two humps. The simple rules of shaping a histogram (don't push tones off the edges; evenly distribute them whenever possible; don't segment tones into two equal humps like a camel's back) and the rules of adjusting an image (don't overcorrect for brightness; balance your lights, darks, and midtones whenever possible; don't sacrifice your midtones for darks and lights) correspond to one another. You'll be surprised how many corrections you can make "flying on instrumentation alone"trusting the histogram to tell you how far to go, and when you're in danger of going too far.
For this example, the highlights were dark enough already. I needed to lighten the shadowy areas to give the picture more punchespecially to bring Katie's bright red glove toward you (because vivid colors tend to convey the illusion of dimension better). I adjusted Lighten Shadows significantly higher, and then added a little to Midtone Contrast to compensate.
To finalize your adjustments, click OK.
If your digital camera includes a scene mode such as Snow or Beach, use it when taking a photo with a bright background, and your subject will not appear so dark in the resulting photograph.
Adjust Background Layer and Merge
On the Layers palette, choose the Background layer. From the menu bar, select Enhance, Adjust Lighting, Levels. Using the method described in 138 Improve a Dull, Flat Photo, reduce the white point until you've restored your snowy whites. Your subject will be unaffected. With this method, I significantly lowered the white point from 255 all the way down to 186 without losing any information about the crisp, clear, fresh snow.
To reduce the number of layers down to one, select Layer, Flatten Image from the menu bar.
View the Result
When you're satisfied with the result, make any other changes you want and save the PSD file. Resave the image in JPEG or TIFF format, leaving your PSD image with its layers intact so that you can return at a later time to make new adjustments.
My original photo suffered from a phenomenon common to digital cameras: The brightness of the snow overwhelmed the light detectors, even when the camera was set for bright outdoors. As a result, Katerina's colors were muted and dull. I made Shadows/Highlights adjustments to brighten her clothes, but had my image been one undivided layer, the same changes I made to her clothes and skin tones would have made the snow pink. By separating the snow from the foreground, I was able to shield the snow from the changes I made to the color channels, and then applied color-safe changes to the snow.