176. Change a Color Photograph to Black and White
Before You Start
92 Create a New Image Layer
136 About an Images Histogram
149 Sharpen an Image
138 Improve a Dull, Flat Photo
Although it literally takes one step to make any color image monochromatic in Photoshop Elements, there's no guarantee that the result will be an attractive black-and-white image. Professional photographers know there are special effects that can be achieved only with black and white; when you add color, your eyes are no longer drawn to the same points of drama and impact.
But you generally can't obtain a quality black-and-white image simply by removing the hue and saturation data from a color image. Your eyes naturally distinguish elements of the scene you're viewing now by contrasting their colors against one another; if you were to remove the color, the contrast would go away as well. The great cinematographers of the 1930s and '40s knew this, and would construct movie scenes with bold, surrealistic lights and shadowsin the real world, at leastthat looked majestic and beautiful in monochrome. For you to obtain a similarly beautiful monochrome image from what might very well be a beautiful color image, you might have to generate some unrealistic contrasts in color that form dramatic but realistic contrasts in monochrome.
For comparison's sake, here's the one-step method for making any image monochromatic: With the image open in the Editor, select Image, Mode, Grayscale from the menu bar. Click OK at the warning. (Okay, two steps.) In many cases, what looked like perfectly distinguished shades in a color photograph become murky and muddled when the hue and saturation data is removed.
Create New Layer for Red Channel
Open the image in the Editor in Standard Edit mode and save it in Photoshop (*.psd) format. With the Background layer selected in the Layers palette, choose Layer, Duplicate Layer from the menu bar. Name the new layer Red.
Filter Out Green and Blue
With the Red channel selected in the Layers palette, select Enhance, Adjust Lighting, Levels from the menu bar.
In the Levels dialog box, enable the Preview check box so that you can see the effect the changes you are making have on the image. From the Channel drop-down list at the top of the dialog box, select Green. For the Output Levels settings, in the second text box (where it currently says 255), enter 0. Immediately, your image should look pink and purple.
For best results, consider making color corrections and levels adjustments to your color image to perfect it before you take the trouble to convert it to a black-and-white. See 138 Improve a Dull, Flat Photo for some ideas.
From the Channel drop-down list, select Blue, and in the second Output Levels text box, enter 0. You should now be seeing your image as though you were wearing red-tinted glasses.
Why are we making everything red? Why aren't we filtering out everything except blue or green? As photographer Ansel Adams discovered early in his career, applying a red filter to his camera lens enabled him to capture daytime landscapes with either bright or highly variegated skies. In an Adams photo, skies often look very bright (at midday) or serenely dark (at sunrise or dusk). At any time of day, Adams could establish a bold contrast between his sky and his subject matter on the ground. Adjusting an image's red channel performs the digital equivalent of applying a red filter to your lens. For indoor portraits and scenes, if there's not enough detail in the red channel, you might have better luck with the blue or green channel instead.
Adjust Levels to Build Contrast
In the Levels dialog box (you didn't click OK yet, did you?), from the Channel drop-down list, select RGB. Looking at the histogram in the middle of the dialog box, adjust the black and white pointers, if necessary, so that they point to the edges of the graph.
Slide the gray pointer (the one in the middle of the histogram) on the graph to the left, and watch your image as you do. You should notice that the middle tones become lighter, while the brightest and darkest tones remain with little or no change. As you slide the pointer to the left, you increase the RGB channel's gammathe rate at which the gradation from black to gray speeds up, and from which the gradation from gray to white slows down. With the gamma pointer more to the left, pixels in the image tend to become brighter faster. Now click OK.
Apply Unsharp Mask
To create sharper edges and brighter highlights that remain crisp without becoming blocky, use the Unsharp Mask filter. From the menu bar, select Filter, Sharpen, Unsharp Mask. In the Unsharp Mask dialog box, set Amount to 100%. It can be more, but we don't want to create halos around the bounce-light areas. Set Radius to 3.0 pixels. This setting brightens some of the brightest spots without making them larger or extending them into the midtones and shadows. Finally, set Threshold to 25 levels. This is a low settingany lower, and we'd over-darken the shadows; any higher, and we'd lose detail in areas like the leaves of the trees. We don't want to convert them into big clubs. Click OK.
As you drag the gray pointer on the histogram, notice that you're creating three zones of relative brightness within your imagewell-defined darks, well-defined brights, and midtones. The middle value under Input Levels increases as you slide left. You'll want to drop the gray pointer at a location far to the left of a realistic setting for an undamaged color imageprobably at 2.00 or higher.
Remove Red Tint
Now let's start the process of removing the red tint from the image. From the menu bar, select Enhance, Adjust Color, Remove Color. For the time being, your image will appear to be murky gray.
Adjust Levels to Restore Balance
From the menu bar, select Enhance, Auto Levels. This command performs the same magic as balancing the histogram (Levels), restoring full luminance to the white points. What had been the brightest red on your earlier red-tinted layer is now the brightest white in your image.
View the Result
After you're satisfied with the result, make any other changes you want and save the PSD file. Resave the result in JPEG or TIFF format, leaving your PSD image with its layers intact so that you can return at a later time and make different adjustments if you want.
The best black-and-white images have clearly discernable bright and dark areas, even if the subject matter is a darkened room or a bright day in the park. Film developers understand this and apply their skills in the darkroom to give images the appropriate contrasts, even when the film lacks it. What you've done here is set the range of contrast from the darkest possible to the brightest possible shade of gray, made your middle hues brighter, and the contrasts between all three groups of shades crisper. All these elements generally define the best technically composed monochrome images.