Zombie Effect Via Mapping a Texture
You will need two photos for this tutorial, a photo you want to apply the texture to and the texture itself. I am using the two photos below:
Open the photo you want to apply the texture to. First you will need to select the channel with the best image contrast. Switch over to your Channels panel located on the layer palette.
Click on the Channels name tab at the top of the group to select it. You'll see three color channels listed - Red, Green, and Blue - along with a composite RGB channel at the top. You need to select the channel that will give you the highest amount of image contrast, the more contrast you have, the better the results you'll achieve with your displacement map. Click on each individual channel (Red, Green, then Blue) in the Channels panel. As you click on each channel, you'll see a black and white version of the photo appear in the document window. Each channel will give you a different black and white version depending on how prominent that color is in the photo. You need to pick the channel that gives you the best image contrast in the person's face. For my picture I choose the green channel.
Once you've determined which channel you're going to use for your displacement map, make sure you have it selected in the Channels panel. I'm using the Green channel, so I'll click on it to select it:
Now you will duplicate this channel. With the channel selected click on the menu icon in the top right corner of the Channels panel and select Duplicate Channel from the menu that appears:
This will bring up the Duplicate Channel dialog box. Select New for the Document option in the Destination section of the dialog box, which will open the copy of the channel as a separate Photoshop document. Name it Green Channel Duplicate.
Click OK to exit out of the dialog box. The black and white image will appear in a separate document window:
Now you are going to get the document ready for the displacement map. First apply a Median Filter To The Displacement Map Image (Green Channel Duplicate). Go up to the Filter menu in the Menu Bar at the top of the screen, choose Noise, and then choose Median:
This will bring up the Median filter's dialog box. Keep an eye on your image in the document window as you drag the Radius slider at the bottom of the dialog box. The slider determines how much detail is removed from the image. The further you drag the slider towards the right, the more detail you'll remove. The idea is to remove as much detail from the person's face as possible while still keeping important edges intact. I set my Radius to 5.
Click OK to exit out of the dialog box. Next, we'll apply the Gaussian Blur filter to finish off our displacement map. Go back up to the Filter menu and this time, choose Blur, then choose Gaussian Blur:
When the Gaussian Blur dialog box appears, use the Radius slider at the bottom of the dialog box the same way you used it with the Median filter a moment ago, keeping an eye on your image in the document window as you drag the slider towards the right to apply more blurring to the image. I used 5.3.
Click OK when you're done to exit out of the dialog box. Photoshop applies the blurring to the displacement map:
Finally, you will convert the displacement map image to the Grayscale color mode. On the menu toolbar select Image > Mode> Grayscale.
Now that you've prepared your image for use as a displacement map, you need to save it as a Photoshop .PSD file. On the menu bar select File > Save As and select .pds as the format. This brings up the Save As dialog box. Give the file a descriptive name. I'm going to name mine "displacement.psd." Make sure you select Photoshop for the Format option so it's saved as a .PSD file.
You are done with the displacement map at this point, so switch back over to your original photo (the one you're going to apply the texture to). If you're still seeing the image in black and white in the document window, click on the RGB channel at the top of the Channels panel to bring back the full color version of the image. The RGB channel isn't really a channel at all, it's simply the composite of the three individual channels and it's what allows us to see the image in full color:
Switch back over to the Layers panel by clicking on the layers tab. Since you want to map the texture to the person's face, you will first need to select it. Use the selection tool of your choice. I used the polygonal lasso tool.
Next you don't want to apply the texture over the eyes so we to omit them from the selection. On the top left of the document window click the subtract from selection option.
Now drag around the eyes to select them.
Next you need to save the selection. Click on Select on the menu bar and click Save Selection.
This brings up the Save Selection dialog box. I'm going to name my selection "face", then I'll click OK to save the selection for later use:
Once you have saved the selection deselect your selections by holding down the Ctrl and clicking D on your keyboard.
Open the texture you are going to be using. You should now have your original image and the texture photo open in their own separate document windows on your screen. Make sure you have the texture photo selected by clicking on it anywhere inside its document window. Then go up to the Layer menu at the top of the screen and choose Duplicate Layer:
This brings up the Duplicate Layer dialog box. Name the copied layer "texture" and select the original image's document as the Destination for the copied layer so that our texture photo appears inside the original photo's document. My original photo is named "girl_face.jpg", so I'll select it as my destination:
Your texture should now appear in your photo document. Resize the texture as needed using the Free Transform tool (Edit> Free Transform).
Now you will load the selection you saved earlier. On the menu toolbar select Select then choose Load Selection.
Photoshop actually saves selections as channels so if you switch back over to the Channels panel, you can see that your selection appears as a separate channel below the RGB channels.
Switch back over to the Layers panel when you're done. You'll see that the selection outlines have reappeared inside the document, although they may be a little hard to see over the texture:
With the selection loaded, make sure the texture layer is selected in the Layers panel (selected layers are highlighted in blue), then click on the Layer Mask icon at the bottom of the Layers panel. This is how your graphic should look at this stage.
Change the blend mode to the texture layer to overlay.
Things are looking pretty good already at this point, but to add even more realism, we're going to use our displacement map to fit the texture around the contours of the person's face. Select the texture layer. To select the layer itself, click directly on the layer mask preview thumbnail:
If we apply our displacement map right now, both the contents of the layer (the texture photo) and the layer mask will be reshaped by the displacement map, and that's because the layer contents and the layer masked are linked together. Unlink the layer from the layer mask by clicking the link between the texture and the mask. The link icon will disappear.
Finally, you're ready to apply the displacement map, and you do that using Photoshop's Displace filter. Go up to the Filter menu, choose Distort, and then choose Displace:
This opens the Displace dialog box. Click OK to accept the default horizontal and vertical scale values. You can play around with these values. The only problem is there is no preview at this step. The Horizontal Scale and Vertical Scale options determine how much impact the displacement map will have on the image. They determine how far the pixels in the image will shift horizontally and vertically.
When you click OK which will bring you up the second dialog box asking you to choose your displacement map. Navigate to where you saved the displacement map then click on the displacement map to select it and click Open. As soon as you open the displacement map, Photoshop applies it to the texture and maps the texture to the contours of the person's face and head.
Adjust the opacity level to your liking.
Here is how my photo turned out.