Create monochrome images from rgb or cmyk images – Adobe Photoshop CS4 User Manual
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USING PHOTOSHOP CS4
Color and tonal adjustments
Last updated 1/10/2010
You can save Channel Mixer dialog box settings for reuse on other images. See “
and “
Create monochrome images from RGB or CMYK images
Monochrome images display color channels as gray values. Adjust the percentage of each source channel to fine-tune
the overall grayscale image.
1
In the Channels panel, select the composite color channel.
2
In the Adjustments panel, click the Channel Mixer icon
, and then do one of the following:
•
Select Monochrome.
•
Select one of the default presets from the Channel Mixer menu:
Black & White Infrared (RGB)
Red=-70%, Green=200%, Blue=-30%
Black & White With Blue Filter (RGB)
Red=0%, Green=0%, Blue=100%
Black & White With Green Filter (RGB)
Red=0%, Green=100%, Blue=0%
Black & White With Orange Filter (RGB)
Red=50%, Green=50%, Blue=0%
Black & White With Red Filter (RGB)
Red=100%, Green=0%, Blue=0%
Black & White With Yellow Filter (RGB)
Red=34%, Green=66%, Blue=0%
Note: You can also choose Image > Adjustments > Channel Mixer. But keep in mind that this method makes direct
adjustments to the image layer and discards image information.
3
To control the amount of detail and contrast in the images before you convert them to grayscale, use the source
channel 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%.
The Total value displays the total percentage of the source channels. For best results, adjust the source channels so the
combined values equal 100%. If the combined values are above 100%, a warning icon appears next to the total,
indicating that the processed image will be brighter than the original, possibly removing highlight detail.
4
(Optional) 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 black; a +200% value makes the output channel white.
Create a hand-tinted appearance for specific image elements
1
In the Channels panel, select the composite color channel.
2
In the Adjustments panel, click the Channel Mixer icon
.
3
Select and then deselect Monochrome.
4
Choose an Output Channel option, and adjust the source channel sliders. (Repeat this step as desired for each
output channel.)