Tuesday, January 30, 2007
Seeing In Black & White
Create striking monochromatic images from your color digital photos
Doing It In The Computer
As you become more comfortable with evaluating a scene, you may prefer shooting your images in color and selectively converting some to black-and-white using your image-processing program. This gives you the option of creating both color and black-and-white photos, but it teaches you to assess what images translate better to monochrome. There are several ways to easily make the change, as well as advanced techniques that provide greater control.
One of the quickest ways is to convert the RGB image file to grayscale. In Photoshop, go to Image > Mode > Grayscale and convert the open file into a monochromatic image by discarding the color information. The resulting file is created primarily from the green channel, with less information from the blue and red channels.
The RGB image is made up of three black-and-white channels—red, green and blue—and each channel renders the scene differently. You could see the difference if you shot a scene in black-and-white through a red, a green and then a blue filter. The red filter would likely produce a more contrasty scene than the green filter, while the blue filters lighten expansive elements that are dominantly blue, such as water and skies. The blue filter also may reveal electronic noise produced by the CCD.
Using Color Channels
The Channel Mixer (Image > Adjustments > Channel Mixer) affords great control over the creation of black-and-white photographs. When the Channel Mixer dialog box is open, click on the Monochrome option at the bottom of the window; then adjust the red, green and blue channels to vary the tone and contrast of the image. Colors close to those of the filter will appear lighter and thus increase or decrease the contrast between them and other tones. This can be a significant advantage when you want to increase the contrast between two colors that appear close in tone. A red flower against a pattern of green leaves will have a more dramatic contrast if the red channel is emphasized over the green, for example. This is because the red flower will be lightened while the green will darken, thus increasing the contrast.
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