Blur effect is not visible

Symptoms

If one or more of these match what you are seeing, you are on the right page.

• •The blur control moves but the element stays sharp
• •The blur appears banded rather than smooth
• •Blur works on images but not on shapes
• •Performance drops sharply once blur is added

Causes and fixes

Ordered from most to least likely. Work down the list — each cause is paired with what to do about it.

1. 1

   The radius is zero.

   Raise the radius. For image Gaussian blur the practical range is 0–200px; at 0 nothing is applied.

2. 2

   A directional, radial or zoom blur is configured without its driving parameter.

   Directional blur needs a distance along its angle, radial blur needs a strength around its centre point, and zoom blur needs a strength radiating from its centre. Set the parameter, not just the type.

3. 3

   Blur quality is set low.

   On image blur filters, Quality of Low or Medium produces visible banding. Raise it to High at the cost of extra computation.

4. 4

   The blur is on the wrong object in the stack.

   Shape-level blur applies to the whole element after its fills and stroke are composited. For image filters, order matters — a sharpen after a blur partially recovers detail, while a blur after a sharpen obscures it.

5. 5

   GPU memory pressure is limiting the effect.

   Blur requires an offscreen buffer holding a copy of the pre-blur pixels. Under VRAM pressure quality can be reduced. Profile the element to see how many buffers it needs.

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