Instruction Manual

Chapter 7 Basic compositing 243
When working in a 3D group, changes in depth order aect the Stencil and Silhouette blend
modes dierently. For example, if you have two layers in a 3D group and the upper layer is set to
Stencil Alpha or Stencil Luma, the blend mode remains in eect when the upper layer is moved
behind the lower layer in Z space. If you have two layers in a 3D group and the upper layer is
set to Silhouette Alpha or Silhouette Luma, the blend mode does not remain in eect when the
upper layer is moved behind the lower layer in Z space.
When you use the Stencil or Silhouette blend modes in a group set to the Pass Through blend
mode, the resulting eect carries down through every layer in every group that lies underneath it
in the Layers list, unless the group that contains it is rasterized. This is a powerful, but not always
desired eect, because it prevents you from placing a background group to ll the transparent
area. You can limit the Stencil or Silhouette blend mode to aect only those layers in the same
enclosing group by setting the group’s blend mode to anything other than Pass Through. For
example, if you set the enclosing group of the two layers in the Silhouette Alpha example to
Normal, then add a group underneath containing additional layers, those layers show through
the transparent areas created by the silhouetted group.
Mask-Aecting Modes
The following blend modes modify the alpha channel of the layer to which the blend mode
is applied.
•
Stencil Alpha: Uses the alpha channel of the aected layer to crop out all non-overlapping
parts of layers and groups underneath it in the Layers list.
Object used for stencil ResultObject underneath
•
Stencil Luma: Does the same thing as the Stencil Alpha blend mode, but uses the aected
layer’s luma value to dene transparency. Stencil Luma is useful if the layer you want to use for
cropping has no alpha channel of its own.
67% resize factor