Layers in Photoshop 1

What are Layers?

Stonehenge layersStonehenge merged layers

Photoshop has a powerful tool called layers, as do several other image processing programs. The idea of layers is exactly what the name implies, there are two or more layers that build up your image. The example on the right shows an image created from two layers, one with a photograph, the other with print. (Images from Elated online site.)

We can think of layers like tranparencies with images on them that are overlaid to create the final image. Several layers can be used to create an image and may contain such things as photographs, graphics, print. Photoshop defines several types of layers and enables us to combine layers in a varety of ways.

By building parts of our image or adjustments to our image in layers, we have more control over the production process. We can work with a single layer or a combination of layers. Once we make changes on the image itself, by flattening the layers together or making adjustments directly on a given layer, we cannot easily make changes to one part of the image.

Types of Layers

P.E. has several types of layers.

The first layer is called the background layer. It has, for example, the photograph loaded into the P.E. editor. Effects like opacity and masking described below cannot be applied to the background layer; however, the background layer can be changed to a regular layer so these can be applied.

Opacity

A layer can have an opacity defined. 100% opacity means that this layer will block out anything below it, except where it is transparent. A lower opacity will let through the images below according to the level. 0% opacity means the layer will not show. The level of opacity for an adjustment layer affects the degree to which that adjustment is applied to the layers below it.

Masking

Some layers can be masked to let only part show. For example, if we apply an adjustment layer, we can modify its effect over the whole image with opacity or we can mask the effect so it applies only to part of the image. Create the adjustment effect, such as hue and saturation. Adjust the opacity to see its effect. Then set the foreground to black and draw on the image (be sure the adjustment layer is selected in the layers palette). The part of the mask (shown on the layer) that becomes black eliminates the adjustment effect; it only shows where white is left. Alternatively, set the mask to all black (set foreground to black and type alt-backspace), then set the foreground to white and use a brush to paint the parts where you want the effect to apply. The rule is the same -- no effect where the mask is black, effect where the mask is white.

An effect like a fill layer can also be masked in the same way as the adjustment layer.

With a few steps, you can also put an overlay of one photograph (or other pixel-based layer) over another so that it is masked. This involves using three layers: one for the background photograph, one for the overlay photograph and one for the masking.

  1. Open your background photograph.
  2. Open your overlay photograph in the editor, so you have two edit windows.
  3. Activate the move tool (upper left in the palette or type V) and drag the overlay photograph on top of the background photograph. This will create a second layer containing the overlay for this edit window. Close the other window.
  4. Create a new blank layer between the other layers (create the layer, then drag it down or just hold the control key when you create it).
  5. Click the top (overlay) layer and click Ctrl-G to group these two layers - the overlay should disappear.
  6. Click the blank layer to make it active.
  7. Make the foreground color black and paint on the blank layer to make the overlay appear. To adjust the degree to which the overlay appears, change the opacity of the blank (mask) layer.

Another way to get just a part of one photograph to appear in another follows:

  1. Open your background photograph.
  2. Open the photograph with the selection that you want to move.
  3. Use appropriate selection tools to select the part that you want to move.
  4. Be sure that both windows are visible.
  5. Activate the move tool (upper left in the palette or type V), and click and drag the selection onto the background image and drag it to the desired position.

References:

Elated

Photoshop Elements Help - Using Layers

webreference.com