Blur Banding

[user_deleted]

Hello,

I have some artifacts in an image I am working on and I they think have been caused by a blur. They looks like concentrics bands and I wonder if it is a matter of increasing the bit depth of the image....does anyone knows what I am talking about and can help me to fix it?

Thank you !

[user_deleted]

kinda hard to give sound advice without knowing more, so if you can upload a sample file somewhere and post the script i'm sure you get more info.

but if it's really a banding issue, yes, usually increasing the bit depth will fix that
++ chris

[user_deleted]

HI,

Even i have faced these Banding Problem. Banding can be in your image or your image may be fine, it can be because of the monitor also, if the monitor is only 8-bit.

how to check whether its an image banding or Banding is because of monitor? Simple... just check which channel is showing the banding very much that channel on in ur viewer, introduce Brightness node and reduce the value (.25), then put blur node with value 0( just to break concatination), introduce another brightness node and give value4, if the banding has grown up or changed, its an image Banding, in othercase, the banding looks the same its because of the monitor.

i have used Filter/Grain node with the value of .2 in size and density, you can increase according to your sc.

thanks

QUOTE(zem @ 11/22/07, 02:26 AM) [snapback]276855[/snapback]
kinda hard to give sound advice without knowing more, so if you can upload a sample file somewhere and post the script i'm sure you get more info.

but if it's really a banding issue, yes, usually increasing the bit depth will fix that
++ chris

[fxnurbs]

You can work in 16bits or float on few nodes to fix that kind of problems.
creat a node bytes (Others) put it in 16 or float, do your blur and stuff,
after that, add an other bytes node to return in 8bits.
Only what is inside the 2 bytes nodes will be computed in 16 or float.
faster that do all in 16 if you have a big tree

Jazfx

[user_deleted]

Ya, when grain develops due to grading in shake yes you are right, use 16-bit then do whatever treatment you want to give to the layer.

Some times the texture CG people use is not so high quality, as a result banding is seen in the input only, and its magnified when color corrected or translated, in that case we can use the above method of graining the sc.

thanks

QUOTE(fxnurbs @ 01/16/08, 02:35 PM) [snapback]279718[/snapback]
You can work in 16bits or float on few nodes to fix that kind of problems.
creat a node bytes (Others) put it in 16 or float, do your blur and stuff,
after that, add an other bytes node to return in 8bits.
Only what is inside the 2 bytes nodes will be computed in 16 or float.
faster that do all in 16 if you have a big tree

Jazfx