Masks

If you create 

transparent areas

 in a layer using a 

transparent gradient

, the shape of the transparent 

areas is controlled by the selected 

coloring algorithms

. Certain colors in the gradient are transparent, 

so those colors will become transparent in the layer, too. This means that you cannot use this method 

to create arbitrarily shaped transparent areas.

If you use 

transformations

 instead and set the opacity of the 

solid color

 to less than 255, you can 

create arbitrarily shaped transparent areas in the layer. You do need a transformation that will output 

the area you need, but you could write it yourself. Still, a limitation of this technique is that pixels are 

either set to the solid color (transparent), or they are colored according to the gradient and the 

selected coloring algorithms. You can only create sharp edges, not smooth transitions.

Masks overcome these problems. A mask is an invisible layer that is attached to the layer that needs 

transparent areas. The mask contains transparent areas, that are created with an ordinary 

transparent gradient. Since the mask is invisible, these transparent areas are invisible as well. 

Instead, the layer owning the mask "borrows" the transparent areas of the mask. The shape of these 

areas is defined by the selected 

fractal formula

, the selected coloring algorithms, and the gradient of 

the mask. The shape is independent from the layer owning the mask.

The layer that needs 

The mask, with transparent 

  The layer with the mask applied.

transparent areas.

areas.

As you can see, the layer uses the transparent areas of the mask. The rest of the mask layer is 

ignored.

Layers can have multiple masks to add differently shaped transparent areas. If the layer contains 

transparent areas itself (for example created with a transparent gradient), these are also taken into 

account.

Next: 

Working with masks

See Also

Tutorial: Masking

Layers

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