Working with Layers

Blending Layers

A blend mode determines how pixels of the upper layer interact (or blend) with pixels of a lower layer. Blending applies to objects in the same way as to layers. So, to make reading of this page easier, we'll talk only about layers.

To select a blend mode, use a drop-down menu at the top of the Layers panel.

The Layers panel

To see any visual effect from applying a blend mode or transparency, the upper layer should overlap the lower layer(s).

Transparency

Making a layer transparent is one of ways to mix the color of its pixels with pixels of the layer beneath.

When you decrease the Opacity parameter in the Layers panel, you make the contents of the layer more transparent. This increases the impact of the lower layer pixels on the result.

Opacity 100%
Images overlap at 100% opacity.
Opacity 70%
Images overlap at 70% opacity.
Opacity 20%
Images overlap at 20% opacity.

Layer Blending

The default blend mode is Normal. If the top layer is opaque, then only it determines the color. Otherwise, the result depends on the color of the top layer pixel, on the level of its transparency, and on the color of the underlying layer pixel.

The rest of the blend modes calculate color in a more complicated way. But they always take the transparency onto account.

Let's look at a few examples.

Normal blend mode
Blend mode Normal

In the earlier subsection, we can see the Normal blend mode with different level of opacity applied to the upper layer.

Multiply blend mode
Blend mode Multiply

The Multiply blend mode makes the overlap area darker. Within grayscale, if we use 0 for black and 1 for white, then two gray colors with level 0.5 will blend into a dark gray at 0.25.

Screen blend mode
Blend mode Screen

The Screen blend mode produces brighter colors. In the same example as we used for Multiply, two gray colors at 0.5 each will create light gray with level 0.75.

Difference blend mode
Blend mode Difference

The Difference blend mode creates lighter colors when the colors you blend are different. Blending similar colors make the overlap area dark. Blending identical colors create black. Blending with black produces no change.

If you wish to read about other blend modes, please read the Blend modes article on Wikipedia.