Pro Techniques

Color can thrill, color can dazzle, but often a black and white or monochrome image is more powerful. Black and white may better convey the feeling you want to evoke for a particular image--more dramatic, more abstract. Paradoxically, even when you know that you want a final photo in black and white, you should shoot digitally in color, as you should scan a film or print original in RGB color. All the color information allows you to tweak and fine-tune your conversion as if you were using color filters over your lens when shooting traditional black and white film. Even if your digital camera has a gray scale or black and white shooting mode, don't use it. You can always convert a color image into monochrome, but you'll have to resort to hand coloring if you want to transform a black and white image into a color version.

I've performed the conversions shown here with Adobe Photoshop CS2, but many of the techniques will work with earlier Photoshop versions, too. Some can be performed in Adobe Elements and other software programs, as well. However, Elements does not include the powerful Channel Mixer. Always start by making a copy of your image and working on the copy. Save the original file in a safe place.

All Photos © 2005, Howard Millard, All Rights Reserved

Gray Scale Mode
By far the easiest way to convert a color file to black and white is to open the photo and choose Image>Mode> Gray scale. Sometimes, you'll get a good looking conversion. This one looks rather drab and lacking in contrast. In a dialog box, you'll be asked if it's OK to discard the color information. Since you're working with a copy, click OK. Note that when you use this option, your file size is reduced to about 1/3 of the color file size, and the mode is automatically changed to gray scale. Therefore, if you later want to add a tone, such as sepia or blue, you must return to the RGB mode. To do this, choose Image>Mode> RGB color.

Lab Color
For problem images, including those that are very dark or very light, try Image>Mode>Lab Color. Then Window>Show Channels. If you see less than four channels in the palette that pops up, click on the little box at the top right of the channels palette to expand it. Delete the b channel by dragging it to the trash at the lower right inside the Channels palette. When you do this, the Lab channel will disappear, too. The Lightness channel will be renamed #1 or Alpha 1 (depending on which version of Photoshop you're using), and the other channel will now appear as #2 or Alpha 2. Now, drag #2 into the channels trash can, leaving only #1 or Alpha 1. Finally, choose Image> Mode>Gray scale and you're done. For this flower, the LAB conversion is the lightest so far, and in my opinion, not the best. However, the LAB method often produces good results.

The Channel Mixer
Offering by far the most powerful controls for black and white conversions, Photoshop's Channel Mixer is available as an adjustment layer in Versions CS and CS2. Using the Channel Mixer effectively does require a bit of practice. Let's convert an outdoor portrait photo with a wide range of colors.

To access the Channel Mixer, open your color image in Photoshop and choose Layer>New Adjustment Layer>Channel Mixer. Accept the default settings in the dialog box that appears and click OK to bring up the Channel Mixer dialog shown here. Click the Monochrome check box at the bottom of the box, then the Preview check box. Your photo will instantly be transformed to black and white. The default setting of 100 percent red would rarely be my first choice.

Sliders allow you to adjust how much of each color contributes to the black and white conversion. Using 100 percent red is like shooting black and white film with a red filter over the lens--it darkens blue skies dramatically and pumps up contrast. A 100 percent green is like using a green filter to lighten green foliage. Setting 50 percent red and 50 percent green simulates the use of a yellow filter.