Converting A Color Photo To B&W II

© 2002 Gregory Georges

© 2002 Gregory Georges

15.1

© 2002 Gregory Georges

15.2

© 2002 Gregory Georges

ABOUT THE IMAGE

Purple Iris Canon EOS D30 digital camera mounted on a tripod, 100mm macro, f/2.8 ISO 100, RAW setting, 1/4 @ f/14, 1440 x 2160 pixels, edited and converted to 9.3MB .tif

In this technique, you use the Channel Mixer to create a custom mix choosing from each of the three channels to convert the color image into a black and white image. While this technique offers much more control than Technique 14, it can be time-consuming to try various combinations and permutations. If you frequently convert color images to black and white images, this approach should be compared with Technique 14 and Technique 38.

STEP 1: OPEN FILE

■ Choose File ^ Open (Ctrl+O) to display the Open dialog box. Double-click the /15 folder to open it and then click the iris-before.tif file to select it. Click Open to open the file.

STEP 2: EXAMINE EACH CHANNEL

■ Choose Window ^ Channels to display the Channels palette if it is not already displayed. The Channels palette should look like the one

9

*

RGB

1

Red

arl+1

s

Green

Ctrl+2

9

L

Blue

Orl+3

jJ Hi shown in Figure 15.3. Click the Red channel (Ctrl+1) in the Channels palette to view the red channel. Then click the Green (Ctrl+2) and Blue (Ctrl+3) channels to view them. Figure 15.4 to Figure 15.6 show each of these three channels. Note that you can tell what channel or channels are being viewed at any time by looking at the document title bar.

Each of these three different channels shows an entirely different black and white version of the colored iris. Looking at these, you can now begin to understand how much control you will have over how your final image will look — that is if you learn how to mix the channels properly.

Incidentally, I should make the point that if you like one of these versions, you are already done. Just click and drag the two channels that you don't want to use onto the trash icon at the bottom of the Channels palette. You are then left with a grayscale image.

STEP 3: USE CHANNEL MIXER TO MIX CHANNELS

I like the image found in the blue channel; it is a good high-contrast image that shows the detail in all parts of the flower. However, I like parts of the green channel as it shows in more detail in the background. So for simplicity's sake and to match my preferences (yours will undoubtedly be different), combine just the blue and green channels and not use any of the red channel.

■ Click the RGB channel in the Channels palette to highlight all channels.

■ Choose Image ^ Adjustments ^ Channel

Mixer to get the Channel Mixer dialog box shown in Figure 15.7. Click in the box next to Preview (if it is not already checked) to turn Preview on. Click in the box next to Monochrome.

■ As we don't want to use any of the Red channel, type 0 in the % box in the Channel Mixer dialog box. Because the Blue channel offered provides most of the desired details, slide the Blue slider to 80%. To avoid some strange effects, all three channels ought to total 100%. Therefore, slide the Green channel slider until it reads 20%. Click OK and your image should look like the one shown in Figure 15.2.

■ If you don't like these results, choose Edit >-Step Backwards (Alt+Ctrl+Z), then try again until you get your desired results.

The differences between this mixed-channel version and just the blue channel version are subtle, but we have accomplished what we wanted. Using Channel Mixer you have incredible control over your image — more so than you would ever have in the darkroom or when shooting black and white film and using assorted color filters. The problem with using the Channel Mixer is that it is difficult to compare various mixes. If you are serious about black and white photography, I suggest that you consider using the Convert to B&W Pro plug-in, which Technique 38 covers.

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