Hi everyone, we have a great tutorial for colour calibration but I somehow don't get it perfect. I thought it would be nice to have a thread to discuss and gather tips for reaching the perfect colours. So feel free to add your expertise below.
Common issues I experienced so far:
- green cast on yellow
- dark grey reproduced as green
- dark brown reproduced as red
My understanding of the settings:
Whitelevel: Maximum brightness of the colour
Gamma: Brightness curve of the colour (outputColour = inputColour^Gamma)
Pure colour settings: Additional colour mixed into pure colour in order to reproduce TV image
Threshold: Data below set value will be lost
Temperature: ? (Is there a difference to whitelevels?)
Saturation: Amount of general colour (low settings will mix the other two colours into the output to reduce saturation, right?)
Brightness/Luminance: Amount of white (increases or decreases the output values of all colours at the same time)
Now to my problem:
I used the wiki etc. but there is an issue that I can't fix and maybe it's my perfectionism
I got my white levels fine. Green and especially Blue are way to bright so I reduce them significantly. White is alright then. I use the grey scale pictures to calibrate the gamma values. So I get a nice grey. Now comes the problem. If I am around a gamma of 2.5 or higher, dark colours are fine. Even a dark brown is somewhat possible. Problem is that midtones are way to saturated. If I reduce the saturation I lose most of the colour in bright colours and a decent amount in pure colours.
So another option is to reduce gamma to around 2. That way midtones become brighter and therefore less saturated. But then dark colours become way to saturated and intense. For example a subtle dark brown becomes a very saturated red. Another effect is that the Leds light up on black which shouldn't happen. Of course a threshold solves this but then you lose colour nuances. (Example: threshold=0,2=51; 200/50/0 will be 200/0/0)
I don't really know how to fix this. Also how does the temperature effect the colours? Whitelevel is the maximum brightness of the colour. But what does temperature do?
Lets gather some input. I am sure some of you encountered this. Maybe we can also think of ways on how to improve the colour processing algorithms. I think that the more people understand how hyperion processes the colour, the more ideas will come on how to improve it. One way that was discussed is to reduce saturation for dark colours. But maybe you have got more ideas.
Cheers.
doc.ex