Feathering versus Gaussian Blurring

Gaussian blurring is a technique used to blur the whole vector object—like defocusing.  It is a bitmap effect and the blurring can simulate the edge-softening effects of feathering.  Most other software offers Gaussian blurring, but if the purpose is to soften just the edges, Gaussian blurring is not a suitable choice.

To blur an object in Xara, the Live Effect tool must again be used.  Simply select the object to be blurred, select the Live Effect tool, click the New button on the infobar, and select the Enhance Live Effect as shown in Figure 3.1.  This reveals the Enhance dialogue.

Figure 3.1.  To apply a bitmap feather, select the object, click on the Live Effect (LE) tool, click on the New button on the infobar, and select Enhance from the dropdown list.  The Enhance dialogue appears.

The bottom right control symbolised by  is a blur and sharpen control combined.  Dragging the slider to the left applies a Gaussian blur to the selected object in real time as shown in Figure 3.2.

Figure 3.2.  A 96 dpi Gaussian blur is applied to a 96 dpi bitmap.  The LE tool infobar can be used to alter the blur effect resolution.

Note: While Gaussian blurring is no substitute for feathering, there is one interesting caveat with Xara’s implementation of feathering.  When feathering objects with sharp points, the feathering process can generate, at times, noticeable artefacts.  This is due to how points are feathered relative to edges, and is highlighted in Figure 3.3.  Usually, this is not noticeable, but is something to bear in mind.

Figure 3.3.  Feathering can introduce artefacts at sharp points; Gaussian blurring does not.  The artefacts are infrequently noticed however.

Final Comments

Feathering is an exceptionally powerful feature, and very few graphics software to date offers true vector feathering, and certainly not with the same level of slickness offered by Xara.

In general, it is rare that there would be a need to use a bitmap feather on a vector object.  Bitmap feathers would most frequently be used on bitmaps when the alpha channel was to be ignored.  Most of the time, a vector feather is most suitable for feathering needs.

© Xhris