1.1: Why does 'banding' appear on certain monitors and how do monitors interpret colours from Lumion and other 8-bit software.
2.1: Reference: Zendesk Support Request
2.2: Explanation:
Colour banding on 8 bit TVs and monitors
You might know that an image consists of a red, green, and blue 'channel'.
Most monitors for PCs only allow you to display 256 possible red colours for the red channel, 256 possible green colours for the green channel and 256 possible blue colours for the blue channel.
By mixing the 3 channels, the total number of colours that can be displayed on this sort of monitor is 256 x 256 x 256 = 16.7 million different colours per image. This 'colour depth' is known as 8 bits per channel. Lumion also renders Photos and Movies with 256 colours per channel.
In the video capture below, you can see how the red, green and blue colour values from 0 to 255 only change by 1 or 2 numbers at a time as I move the colour picker over each 'colour band':
In other words, the fact that we only have 16.7 million possible colours per image at our disposal on 8 bit TVs and monitors can result in visible 'colour banding'. For instance, when displaying natural gradients (like sunsets, dawns or clear blue skies).
You can read more about this technical limitation in the Wikipedia article below:
There is no way to avoid this completely on a monitor or TV that can only display 8 bits per channel as it's a hardware limitation. But there is a way to make it less noticeable (read on to find out how).
No colour banding on 10 and 12 bit TVs and monitors
Over the past few years, TV manufacturers (and some high-end monitor manufacturers) have started to produce TVs and monitors that support 10 bits per channel instead of 8. A small number of TVs and monitors even support 12 bits per channel. Those TVs and monitors tend to be extremely expensive. A TV or monitor that supports "true" 10 bits per channel is also quite expensive.
With 10 bits per channel, you get 1,024 possible colours for each of the red, green and blue channel. That's over a billion possible colours.
With 12 bits per channel, that's 4,096 possible colours for each channel and over 68 billion colours! That's way more individual colours than the human eye can perceive.
The result is zero colour banding.
So what are your options if you want to avoid colour banding?
There are two ways:
Option 1: Use hardware and software that support 10 or 12 bits:
Avoiding colour banding via better hardware and software would require the following (as far as I know):
From what I gathered, it can be quite difficult to get this to work on a Windows 10 PC.
Also, if you send a rendering to a client, their display almost certainly only supports 8 bits per channel so the hassle of setting up a 10 or 12 bit working environment in your office might be wasted.
Option 2: Use an image editor to make the colour banding less noticeable:
Fortunately, there is an easier alternative: you can use noise, blur, and dithering in an image editor to make the banding less obvious on an 8 bit TV/monitor.
If you type 'how to remove color banding in photoshop' in Google, there are some YouTube videos that show you how to do that.
It won't work in Movies but with a bit of work, you can make it look significantly better for Photos.
Will Lumion be able to render 10 or 12 bits per channel in the future?
As mentioned earlier, Lumion currently only renders images with 8 bits per channel.
If you have the required 10 or 12-bit hardware and software above and you would like to suggest that Lumion should support a 10 or 12-bit output, I'd be grateful if you could please use our Lumion product feedback form so that our developers see that there is a demand.