Layer masks using Channels
PhotoShop: In this example I will show you how you can make a background of an image transparent, for instance if you want to make a path around a product but still use it’s shadow to overlay underlying images. This is also known as an “Alpha channel”.
This first image is the image I want to use, and as you can see it has a white background with an overlying shadow of the product.
Start by selecting a path around the product using your masking tool of choice, preferably the pen tool. But also note that some supplied product images have already an embedded path, you can find those in the Paths palette in most cases.
With the path selected, create a new layer by pressing CTRL+J, this will create a new layer from your selection.
Now create a “Solid Color” adjustment layer and select black for the base color. Your layers palette should now look something like this:
Select the backbround layer and press CTRL+A (select all) and then copy it (CTRL+C). You now have the original image in the clipboard. Select the black adjustment layer again.
Now go to the Channels palette which should be right next to the layers palette and you can see in the bottom of the palette there is a hidden channel called “Color Fill 1 Mask”, select it and make it visible by pressing the “eye” icon.
With the channel selected, paste your clipboard by pressing CTRL+V. Right after pasting, press CTRL+I to invert the image you pasted into the channel. Your channels palette should now look something like this:
Still in the Channels palette, select the eye icon next to the “Color Fill 1 Mask” layer to hide it.
Now select the Layers palette and you will see that an image mask has been created for the black adjustment layer. You can now just delete the background layer as you will not need it anymore. Now your layer palette should look something like this:
And your finished image should look something like this:
As you can see the shadow is transparent, so to finish it up, link the two layers together or merge them (a good rule is to have these layers seperate and select a Multiply blending mode for the shadow layer). You can now drag these layers to another open image and see the effect of your overlaying transparent shadow.
Monday, March 5, 2007 at 20:45
Quite handy when you’ve got a hard-edged (i.e., easily-isolated) foreground image. Thanks for the tip.
Wednesday, August 15, 2007 at 13:31
Photoshop Masking are actually 3 types:
1. Layer Masking,
2. Channel Masking or Alpha Channel Masking, and
3. Path Masking (Clipping Path)
Thanks for the post. I was actually looking for articles relating to these 3 types of Photoshop Masking. Then, I stumbled upon your blog post. As a professional in Photoshop Designing, we know how handy this tutorial is.
You can do the same thing with Channel Masking alone. Here is the process:
1. Choose the best channel (Red, Green, Blue = RGB) that shows the shadow perfectly.
2. Copy the channel by dragging the channel to “New Channel” Button
3. While keeping the New Channel selected, click the Path Tab and select the Clipping Path by holding down the Ctrl or Cmd button.
4. This will select the outlined Laptop in the New Channel
5. Fill the outlined selected area with black (Edit > Fill > Use : Black)
6. Deselect (Ctrl or Cmd + D) and click the layer containing the laptop
7. Click the Channel Tab and then click the New Channel by holding down the Ctrl or Cmd button.
8. Press the Delete button. Wella! backgrounds are gone.
9. If you have a few white left in the shadow, the remove White Matte from the Layer (Layer > Matting > Remove White Matte).
To check if it works with other background colors, create a new layer and keep it below the layer with laptop. Choose a color and kick the bucket on the layer
Tuesday, April 1, 2008 at 7:26
In InDesign to get transparent shadows of objects photographed on white background - this is what i do:
I create a clipping path around the object in Photoshop and save the image with the clipping path. In InDesign i place it once with clipping path and once without. The two images i align on top of each other. The image below - without clipping - i set to mulitply, and the image above is the normal clipped image. Group them. You now have a movable object that has a nice shadow on every background.
Saturday, May 17, 2008 at 9:08
very informative… thanks for sharing…