Large scale monochromatic prints can be a stunning way to present your message.
Black and white images might suggest a past time and place when all photographs were without color. They can evoke a cinematic film noir-like drama with hard contrasts and dark shadows, or they can portray a misty, dream-like quality in a picture. The absence of color can be a real asset in helping to emphasize other pictorial characteristics, such as form and tonality, and can heighten the impact of the image content.

Converting a color photograph into a monochromatic image is a snap with any of several Photoshop CS3s features; however, producing the perfect monochromatic image is more of an art than a science and requires a keen eye, a sensitive hand and the awareness of how best to utilize tonal relationships.

COLOR TO GRAYSCALE
A full color RGB image is composed of three channels — red, green and blue — each containing the component color information. Each pixel in each channel contains eight bits of information, (called 24 bit color). When combined, the three channels can produce up to 16,777,216 potential colors.

When a color is completely removed from an image using the Desaturate command in the Image menu, each of the channel’s pixel values become identical. The lack of disparity between color values produces neutrality. In other words, the number of colors is reduced from potentially more than 16 million to a mere 256 shades of gray. When an RGB color image is converted to a grayscale the process is the same, except that the information is contained on one gray channel instead of three identical color channels. It is difficult to predict what the results of converting a color image directly to a grayscale will be. Simply changing modes doesn’t always produce the best results even though the image may look spectacular in color. Sometimes the image’s tonality flattens, and the result can be really disappointing (see Figure 1) because the conversion algorithm uses averaging to convert the brightness values of the original colors. This process allows no control over the results until after the conversion has been made. Instead, it much more desirable to control desaturation before converting to assure the best results.

CHOOSING CHANNELS
One way to produce a good quality black and white image is to assess each color channel by switching off the visibility icons of the other channels in the Channels palette. Observe each channel’s content in the image window, as in Figure 2 (at left). Select the channel that looks the best and copy it to a new document by going to the Palette Options menu and selecting Duplicate Channel. In the dialog box that appears (see Figure 3, below)., select New Document. The copy is generated as a Multichannel document and needs to be converted to grayscale (Image > Mode > Grayscale) if you intend to edit it. You’ll no doubt have to tweak the image with levels or curves to produce a first rate black and white image.

MIXING CHANNELS
Another tried-and-true method is to swap the channel information from the color image with the Channel Mixer. This variation of the color to black and white technique uses the Channel Mixer on an adjustment layer to combine values of all the channels into a an image with a wide tonal range. The advantage of using the Channel Mixer technique is the flexibility of the process in that all the controls are in one interactive dialog box. This technique also employs a layer mask for more precision and control. Here’s how it’s done.

Open a color photograph.

Choose Layer > New Adjustment Layer.

Choose Channel Mixer from the pop-up menu to display the Channel Mixer dialog box, as in Figure 4 above.

Select the Monochrome checkbox. The image now appears black and white and the Red and Green sliders read 40 percent while the Blue slider reads 20 percent. This produces a rather disappointing monochrome. Adjust the sliders to get more punch and pop out of your image as in Figure 5 above.

Click the Adjustment Layer’s layer mask to target it.

Choose the Brush tool and a medium soft brush from the Options bar brush menu.

Press the D key to set the foreground and background color to the default white and black.

Click and drag over the image to paint the highlights back. Don’t forget that even though the image appears as black and white, it was captured in RGB mode.

Convert it to grayscale (Image > Mode > Grayscale) to finish the job.

BLACK AND WHITE
The Black and White feature in Photoshop CS3 controls all the characteristics of your color to black and white conversions in one concise interface. It’s a one-step process that creates monochromes by sourcing tonality from the color information. The command is similar to the Channel Mixer in that it lets you target specific ranges of the color in the original image, but it goes beyond just using red green and blue by offering sliders for red, yellow, green, cyan, blue and magenta.

Choose Image > Adjustments > Black and White to display the dialog box, or you can make a black and white adjustment layer (Layer > Adjustment Layer > Black and White). The individual sliders in the dialog box (see Figure 5) adjust the brightness percentage of each color range. Drag the slider to the right to lighten and to the left to darken the gray tones within the range. You can apply preconfigured brightness and contrast values to your black and white images by choosing one from the Preset pop-up menu at the top of the palette. These values simulate photographic filters or specific photo effects.

The Black and White command works only in RGB mode. When you apply the command the image is not automatically converted to grayscale although it appears as a black and white image. It remains in RGB mode until you convert it by choosing Image > Mode > Grayscale.

SEPIAS AND OTHER TINTS
Check the Tint checkbox to apply an over all color to the image. Drag the Hue and Saturation sliders to modify the black and white image into a sepia tone or other monochromatic colored image as in Figure 6 above.

PRINTING BLACK AND WHITE WITH BLACK
There are a few things to consider when printing a grayscale image. If you choose to print in monochrome mode, only black ink is deposited and is limited to the quantity of ink drops that are deposited by the black ink cartridge — approximately one sixth the amount of full color print. The result is a print that lacks the tonal range, smoothness and depth.

PRINTING BLACK AND WHITE IN COLOR
Printing a grayscale image to a color ink set seems like a logical enough solution, but most printer drivers support grayscales by laying down equal amounts of each color of ink to produce a range of neutral grays. Unfortunately, these mass produced printers are not 100 percent precise, there is variation in the amounts of each ink when applied to the substrate. The results are not perfectly neutral but display a slight tint of either magenta or cyan. It is quite difficult to achieve an absolutely neutral gray with a color ink set but you can control this problem to some degree by working in a calibrated environment.

Another solution is to purchase a variable tone ink set consisting of four to eight shades of gray depending on the printer. Epson makes a series of Ultacrome inks using a three-level black ink system that optimizes the black ink density for various media types. It is available for the Epson Stylus Photo R2400 and Epson Stylus Pro 4800, 7800 and 9800 printers to produce professional quality large-format black and white prints from color or grayscale image files. There are also several third-party grayscale ink sets available for archival inkjet printers.