Adobe 13102498 - Photoshop CS3 - Mac User Manual page 187

• Choose Layer > New Adjustment Layer > Channel Mixer. Click OK in the New Layer dialog box.
For Output Channel, choose the channel in which to blend one or more existing channels.
3
Choosing an output channel sets the source slider for that channel to 100% and all other channels to 0%. For
example, choosing Red as the output channel sets the Source Channels sliders to 100% for Red, and to 0% for Green
and Blue (in an RGB image).
4 To decrease the channel's contribution to the output channel, drag a source channel slider to the left. To increase
the channel's contribution, drag a source channel slider to the right or enter a value between -200% and +200% in
the text box. Using a negative value inverts the source channel before adding it to the output channel.
Photoshop displays the total value of the source channels in the Total field. If the combined channel values are above
100%, Photoshop displays a warning icon next to the total.
5 Drag the slider or enter a value for the Constant option.
This option adjusts the grayscale value of the output channel. Negative values add more black, and positive values
add more white. A -200% value makes the output channel completely black, and a +200% value makes the output
channel completely white.
You can save Channel Mixer dialog box settings for reuse on other images. See "Save and reapply adjustment dialog
box settings" on page 159.
Create monochrome images from RGB or CMYK images
1 In the Channels palette, select the composite color channel.
To open the Channel Mixer dialog box, do one of the following:
2
• Choose Image > Adjustments > Channel Mixer.
• Choose Layer > New Adjustment Layer > Channel Mixer. Click OK in the New Layer dialog box.
Do one of the following:
3
• To set Gray as the output channel, select Monochrome. Monochrome creates a color image that contains only gray
values.
• To create a grayscale, apply a preset channel mix. Photoshop provides six default Channel Mixer presets for RGB
images:
Black & White Infrared (RGB)
Black & White With Blue Filter (RGB)
Black & White With Green Filter (RGB)
Black & White With Orange Filter (RGB)
Black & White With Red Filter (RGB)
Black & White With Yellow Filter (RGB)
To control the amount of detail and contrast in the images before you convert them to grayscale, use the Source
4
Channels sliders.
Before adjusting the percentages of the source channels, view how each source channel affects the monochrome
image. For example, in RGB, view the image with the Red channel set to +100% and the Green and Blue source
channels set to 0%. Then, view the image with the Green source channel set to +100% and the other two channels set to
0%. Finally, view the image with Blue source channel set to +100% and the other channels set to 0%. For best results, try
adjusting the percentages of the source channels so the combined values equal 100%.
Red=-70%, Green=200%, Blue=-30%
Red=0%, Green=0%, Blue=100%
Red=0%, Green=100%, Blue=0%
Red=50%, Green=50%, Blue=0%
Red=100%, Green=0%, Blue=0%
Red=34%, Green=66%, Blue=0%
PHOTOSHOP CS3 180
User Guide