Photoshop Demo 3

4.560/4.561 Photoshop Channel and Mask Demo

Instructor: Prof. Takehiko Nagakura
Last modified: 2011.02.03. by TN
All rights reserved.

Demo 3
The following example combines two images together and creates a shadow using alpha channels. For a simpler method, see Demo 4.

1 Open both marble.jpg and column.jpg in Photoshop.

2 Create a new photoshop file (File>New) that is 450 pixels square.

3
Go to marble.jpg, create a new channel and name it "column mask". (See Demo 1 item 2 for making a channel.)
Go to column.jpg file, select its entire image (Ctrl-A) and copy (Ctrl-C) it into memory.
Go back to marble.jpg, make sure the column mask channel you made is still selected (see the image left), and paste (Ctrl-V) the column image in there. After copying the column image, inverse the image in column mask channel (Ctrl-I).

4
To switch back from the mask channel mode, select RGB channel (including the marble image) by clicking its icon showing in the top row of the Channels pallete. You should now see the marble image on the screen.
Then go to
Select > Load Selection... >
Document should be marble.jpg and Channel should be column mask (see the image left). This will make a selection shaped like the column.

5 Copy the selection (Ctrl-C) into memory, go to the new empty Photoshp file you made, and paste (Ctrl-V) it there. You now see a column shape filled with Marble pattern.
Rename the layer of the pasted image to "marble cross".

6
To create the shadow, make a new layer between marble cross and background and name it "shadow". Make it the active layer. Also, I recommend you to hide marble cross layer for now.

The column channel is in the marble,jpg file, but we can still load it into the current file as a selection as long as the marble.jpg is still open.
Go to
Select > Load Selection... >
In the dialog, Document box should be set there to marble.jpg and you can select Channel to be column mask. Now you see the selction shaped like the column.

7 To blur the edges of the selection, Select > Feather > Set the Feather Radius to 3 pixels. This effect gives the shadow a soft edge.

8 To pick the color of the shadow, click on the foreground color swatch. Make a dark gray color by setting R:50, G:50, B:50.

9 To make the shadow, Edit > Fill > Use: Foreground Color.

10 Finally, show the marble cross layer back again, and use the move tool and adjust the shadow layer so that it is slightly to the bottom right of the marble cross.

		Demo 3 The following example combines two images together and creates a shadow using alpha channels. For a simpler method, see Demo 4.
	1	Open both marble.jpg and column.jpg in Photoshop.
	2	Create a new photoshop file (File>New) that is 450 pixels square.
	3	Go to marble.jpg, create a new channel and name it "column mask". (See Demo 1 item 2 for making a channel.) Go to column.jpg file, select its entire image (Ctrl-A) and copy (Ctrl-C) it into memory. Go back to marble.jpg, make sure the column mask channel you made is still selected (see the image left), and paste (Ctrl-V) the column image in there. After copying the column image, inverse the image in column mask channel (Ctrl-I).
	4	To switch back from the mask channel mode, select RGB channel (including the marble image) by clicking its icon showing in the top row of the Channels pallete. You should now see the marble image on the screen. Then go to Select > Load Selection... > Document should be marble.jpg and Channel should be column mask (see the image left). This will make a selection shaped like the column.
	5	Copy the selection (Ctrl-C) into memory, go to the new empty Photoshp file you made, and paste (Ctrl-V) it there. You now see a column shape filled with Marble pattern. Rename the layer of the pasted image to "marble cross".
	6	To create the shadow, make a new layer between marble cross and background and name it "shadow". Make it the active layer. Also, I recommend you to hide marble cross layer for now. The column channel is in the marble,jpg file, but we can still load it into the current file as a selection as long as the marble.jpg is still open. Go to Select > Load Selection... > In the dialog, Document box should be set there to marble.jpg and you can select Channel to be column mask. Now you see the selction shaped like the column.
	7	To blur the edges of the selection, Select > Feather > Set the Feather Radius to 3 pixels. This effect gives the shadow a soft edge.
	8	To pick the color of the shadow, click on the foreground color swatch. Make a dark gray color by setting R:50, G:50, B:50.
	9	To make the shadow, Edit > Fill > Use: Foreground Color.
	10	Finally, show the marble cross layer back again, and use the move tool and adjust the shadow layer so that it is slightly to the bottom right of the marble cross.

4.560/4.561 Photoshop Channel and Mask Demo

Demo 3

Haldane Liew (original 2003.09.02), Takehiko Nagakura (last mod. 2011.02.03)