Blur

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We all know what a blur does dont we? I dont really need to explain it. Like all filters it is a bit heavy on the processor. If this becomes an issue the blur 'filter' value may be changed. 'Gaussian' is the default (and probably the finest), 'box' is the fastest.

One thing to watch out for is what happens at the edge of the blur. Being a filter, the blur acts upon each pixel according to the values of its neighbors. In the case of an image that stops at its edges, the edge pixels share a border with black, which will be included in the blur filtering. This will effect its quality. In the example below the Crop node crops the CheckerBoard so that all pixels outside past the BoundingBox become zero (i.e. black). The blur processes these black pixels to produce a dark fringe. Deactivate the Crop node to see the blur without the dark fringe.

If you are wanting to blur in order to emulate a defocus, better by far to use a Defocus node.

Press 'Expand' and select and copy everything below this line, then paste into the Nuke node graph.

<pre<noinclude></noinclude>> set cut_paste_input [stack 0] version 9.0 v7 CheckerBoard2 {

inputs 0
boxsize 400
name CheckerBoard1
selected true
xpos -245
ypos -172

} Reformat {

format "1920 1080 0 0 1920 1080 1 HD_1080"
name Reformat4
selected true
xpos -245
ypos -100

} Crop {

box {0 0 1920 1080}
name Crop1
selected true
xpos -245
ypos -24

} Blur {

size 200
quality 25
name Blur2
selected true
xpos -245
ypos 41

} StickyNote {

inputs 0
name StickyNote1
label "Deactivate this Crop node to see the difference in edge qality --->    "
selected true
xpos -561
ypos -31

} StickyNote {

inputs 0
name StickyNote2
label "The Crop node crops the CheckerBoard...\nThis creates blackness outside of the format.\nThis nblackness is included in any blur.   "
selected true
xpos -560
ypos 10

} </pre<noinclude></noinclude>>