Mist is another great tool made by Jed Smith. It creates a diffused and moody feeling, perfect for romantic comedies!

If you want you can see the code (and many other amazing ones from Jed) on his GitHub.
Expand Mist
Group {
name Mist
onCreate "\nif nuke.thisNode()\['f_created'].getValue()==True:\n nuke.thisNode()\['f_created'].setValue(False)\n nuke.thisNode().showControlPanel()"
addUserKnob {20 Mist}
addUserKnob {7 m l soft}
m 0.1
addUserKnob {7 pw l contrast R -1 1}
addUserKnob {7 s l size t "convolution kernel size : range 128 to 2048"}
s 0.1
addUserKnob {26 ""}
addUserKnob {41 useGPUIfAvailable l "Use GPU if available" T Convolve.useGPUIfAvailable}
addUserKnob {41 maskChannelMask l mask -STARTLINE T Convolve.maskChannelMask}
addUserKnob {41 invert_mask l invert -STARTLINE T Convolve.invert_mask}
addUserKnob {41 mix T Convolve.mix}
addUserKnob {6 f_created l "First Created?" +INVISIBLE +STARTLINE}
f_created true
}
Input {
inputs 0
name Inputmask
xpos 180
ypos -705
number 1
}
Input {
inputs 0
name Input
xpos 70
ypos -802
}
Dot {
name Dot1
xpos 104
ypos -750
}
set N31f74100 [stack 0]
Reformat {
type "to box"
box_width {{rint(s*960+64)*2}}
box_height {{box_width}}
box_fixed true
resize distort
black_outside true
name Reformat3
xpos -40
ypos -753
}
Expression {
temp_name0 d0
temp_expr0 hypot(x/width-0.5,y/height-0.5)+mn
temp_name1 d
temp_expr1 pow(d0,p)
channel0 {rgba.red rgba.green rgba.blue none}
expr0 max(0,1/(d*d)-4*(1-s))
channel3 none
name inverse_square
selected true
xpos -40
ypos -705
addUserKnob {20 User}
addUserKnob {7 mn}
mn {{max(1e-8,pow(m,1.8)*10/width)}}
addUserKnob {7 p R 0 4}
p {{pow(2,pw)}}
}
push $N31f74100
Convolve2 {
inputs 2+1
channels rgba
filter_channel rgba.red
filter_bounds format
name Convolve
xpos 70
ypos -705
}
Reformat {
type "to box"
box_width {{"\[exists input] ? input.width : root.width"}}
box_height {{"\[exists input] ? input.height : root.height"}}
box_fixed true
box_pixel_aspect {{"\[exists input] ? input.pixel_aspect : root.pixel_aspect"}}
resize none
black_outside true
name BboxRemove
xpos 70
ypos -634
}
Output {
name Output
xpos 70
ypos -601
}
end_group