The next steps start out with the Layers palette. To create the new contrast enhancing layer, the Background layer is duplicated by dragging the Background layer to the Create a new layer icon at the bottom of the Layers palette. The new layer is renamed as the Contrast layer. Figure 8 shows the Layers palette after the Contrast layer has been added.
With the Contrast layer selected, the Channel Mixer is launched by choosing Image/Adjustments/Channel Mixer. The Channel Mixer (see Figure 9) adjusts the layer by mixing the detail from the three color channels. In other words, the Channel Mixer takes a percentage of the data from the red channel, a percentage from the green channel, and a percentage from the blue channel. The important point is that the photographer gets to decide on what the mixture (i.e., the percentages) will be. For this particular image, it is necessary to increase the amount of the green and blue channels while reducing the amount of the red channel. Since this layer is designed to add contrast to the image without affecting the color balance, the Monochrome box is checked. Some experimentation is required to find the settings that create the desired contrast. The settings shown in Figure 9 create a mixture that works well for this image.