Banding?
Aug 22, 2011 20:08:31 #
In another thread, "banding" was mentioned. What is banding, how do you recognize it and fix it? I'd never heard the term before and I would hate to be unaware of something I could be doing to improve my pictures.
Aug 22, 2011 21:57:30 #
I was the one who mentioned banding in another string...
Banding is when, in a gradation, you can see actual bands of tone rather than a smooth, continuous gradation.
Banding was an infamous problem back in the days of film scans, where skies, which smoothly gradated from blue to white, ended up banding, particularly in 8 bit color.
You see banding all the time in the "digital quality" of HDTV as broadcast. Digital HD looks awful, all the time, particularly in dark scenes. It is due to the 30 to 1 compression used in broadcast (cable and satellite.)
In stills, the classic approach to fixing banding, when you see it, is to select the banded area, and ADD NOISE to that area, which will "blend the bands" in the noise matrix.
The key is not to add too much noise, else suffer further.
Occasionally, after adding noise, you can use a very slight blur to hide the effect, but depending on the blur algorithm you MIGHT just find yourself creating a new banding.
Importantly, banding is quite the culprit in 8 bit color, less a culprit in 10 bit color, and lesser a culprit as the bit rate goes up from there.
Now, all that said... relax... most common photographic situations have nothing in them to promote banding at any standard bit rate, even 8 bit. When the scene is "busy" banding rarely develops if the system has a propensity to band.
Smooth gradations, from small, but detailed midtone to shadow gradations on skin to vast shots of the sky with a cyan-blue to white gradations are the sorts of situations in which banding tends to develop.
Happy Banding Busting!
Richard Brown
Banding is when, in a gradation, you can see actual bands of tone rather than a smooth, continuous gradation.
Banding was an infamous problem back in the days of film scans, where skies, which smoothly gradated from blue to white, ended up banding, particularly in 8 bit color.
You see banding all the time in the "digital quality" of HDTV as broadcast. Digital HD looks awful, all the time, particularly in dark scenes. It is due to the 30 to 1 compression used in broadcast (cable and satellite.)
In stills, the classic approach to fixing banding, when you see it, is to select the banded area, and ADD NOISE to that area, which will "blend the bands" in the noise matrix.
The key is not to add too much noise, else suffer further.
Occasionally, after adding noise, you can use a very slight blur to hide the effect, but depending on the blur algorithm you MIGHT just find yourself creating a new banding.
Importantly, banding is quite the culprit in 8 bit color, less a culprit in 10 bit color, and lesser a culprit as the bit rate goes up from there.
Now, all that said... relax... most common photographic situations have nothing in them to promote banding at any standard bit rate, even 8 bit. When the scene is "busy" banding rarely develops if the system has a propensity to band.
Smooth gradations, from small, but detailed midtone to shadow gradations on skin to vast shots of the sky with a cyan-blue to white gradations are the sorts of situations in which banding tends to develop.
Happy Banding Busting!
Richard Brown
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