How to Clip Layers into Masks in Photoshop CS6
When using Photoshop Creative Suite 6, a clipping mask, the bottommost layer (also known as the base layer) acts as a mask for the layers above it. The layers in the group clip to the opaque areas of the base layer and don’t show over the transparent areas of the base layer.
At this point, you might be saying, Huh? Instead of trying to decipher the definition, a better way to understand a clipping mask is to just create one.
Creating a clipping mask works well if you want to fill type or a shape with different images on multiple layers.
Using the steps that follow, a new document was created with a white background. Using the Custom Shape tool a flower was drawn on the second layer. A drop shadow and inner bevel was added to the flower for extra dimension, but this step isn’t mandatory.
An image of a green meadow and sky was opened and dragged and dropped onto the composite. An image of some tulips was opened, the bouquet was selected, and dragged and dropped onto the composite.
And, finally, some type was created with an applied drop shadow.
Follow these steps to create your own clipping mask:
Open or create an image that has several layers.
Hold down Alt (Option on the Mac) and position your mouse cursor over the line dividing two layers in the Layers panel.
Your cursor changes to two overlapping circles with a small arrow icon. You can also choose Layer→Create Clipping Mask or choose the same command from the Layers panel menu.
Click your mouse button.
This was done three times: in between the type and the tulips layer, in between the tulips and the meadow layer, and in between the meadow layer and the flower shape. Notice how all the images and the type clip to the base layer (the flower shape) in the Layers panel.
Nothing outside the boundaries of the flower shape is visible on any of the layers in the clipping mask. The down-pointing arrow icons beside each layer on the Layers panel indicate that the layers are clipped. The clipping mask takes on the opacity and blend mode of the base layer.