Swapping Channels






Swapping Channels

You can use a fantastic channel technique to recolor an image: Simply swap the contents of the color channels. It works by literally copying and pasting the contents of one color channel to another. Open an image and experiment with this. Some of the results may be wild, but others may be downright lovely.

The following directions swap the contents of the Red and Green channels, but you can exchange any combination:

  1. Open the image that you want to recolor.

    For this example, I’m using the photograph of a white peacock, shown in Figure.

    Click To expand
    Figure: This white peacock is going to have his feathers recolored.

  2. In the Channels palette right-click/Control+click the Red channel and choose Duplicate Channel from the menu.

  3. Click OK in the Duplicate Channel dialog box that opens.

    A duplicate of the Red channel, named Red Copy, appears at the bottom of the Channels palette.

  4. In the Channels palette right-click/Control+click the Green channel and choose Duplicate Channel from the menu.

  5. Click OK in the Duplicate Channel dialog box that opens.

    A duplicate of the Green channel, named Green Copy, appears at the bottom of the Channels palette. You should now have two duplicated channels, as shown in Figure.


    Figure: You should have two copied channels at the bottom of the Channels palette.

  6. Select the Red Copy channel in the Channels palette.

  7. Choose Select>All or press Ctrl+A/z +A.

  8. Choose Edit>Copy or press Ctrl+C/z +C.

  9. Select the Green channel in the Channels palette.

  10. Choose Edit>Paste or press Ctrl+V/z +V.

    This copies the contents of the Red Copy channel to the Green channel.

  11. Select the Green Copy channel in the Channels palette.

  12. Choose Select>All or press Ctrl+A/z +A.

  13. Choose Edit>Copy or press Ctrl+C/z +C.

  14. Select the Red channel in the Channels palette.

  15. Choose Edit>Paste or press Ctrl+V/z +V.

    This copies the contents of the Green Copy channel to the Red channel. You’ve now swapped the contents of the Red and Green channels. How did the colors change in your image? In the peacock photograph, the peacock’s feathers changed to a bright violet.

You can see the results of some channel swapping in Color Plate 54-1.



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