The Apply Image command lets you blend
one image’s layer and channel (the source) with a layer
and channel of the active image (the destination).
Open the source and destination images, and select
the desired layer and channel in the destination image. The pixel
dimensions of the images must match for image names to appear in
the Apply Image dialog box.
Note: If the color modes of the two images differ (for example,
one image is RGB and the other is CMYK), you can apply a single
channel (but not the source’s composite) to the destination layer’s
composite channel.
Choose Image > Apply Image.
Choose the source image, layer, and channel you want
to combine with the destination. To use all layers in the source
image, select Merged For Layer.
To preview the results in the image window, select Preview.
To use the negative of the channel contents in the calculation,
select Invert.
Enter an Opacity value to specify the effect’s strength.
To apply the results only to opaque areas in the result
layer, select Preserve Transparency.
If you want to apply the blending through a mask, select
Mask. Then choose the image and layer containing the mask. For Channel,
you can choose any color or alpha channel to use as the mask. You
can also use a mask based on the active selection or the boundaries
of the chosen layer (Transparency). Select Invert to reverse the
masked and unmasked areas of the channel.