@obe @s7habo Olaf this is a photoshop video but this young man is really good and the principle hold and I think he is offering the type of explanation you are looking for…totally applicable to DT editing color with the channel mixer - Google Suche
Thanks @priort , but I know how channel mixer works.
Problem is to explain it to people who don’t know how the color channels interact with each other. This means that it’s not always clear if it’s necessary to explain the color channels and the color composition itself before you get into explanation about channel mixing.
Just looping you in…I had now doubt you understood it…
Hi’ @priort @s7habo @age @st.raw
Thank you guys for your responses and examples. I really appreciate your input and I will study the material closer in the days to come….
!
I have read the “please help me to understand the “channel mixer” thread a long time ago, and I think this thread and your examples illustrate the (users) problem with this tool.
Channel mixer is complicated, because the red, blue and green channels interacts. I’m sure that you can make some adjustment, observe the changes and deduct why the changes took place looking at the color wheel.
But ideally, it should be the other way around. You observe a problem and decide to use the channel mixer as the appropriate tool to fix the problem and then do it.
The theme in many tutorials seems to be something like: if we add some red to the blue channel, what happens then? This is of course also the basic mechanism. The user manual section covering the channel mixer is rudimental. The destination can be a color channel or grey like in the tutorials but the destination can also be hue, saturation and lightness. What happens here and what’s the purpose of this?
Darktable consists of many wonderful tools (more than 70!), tools that are partly overlapping. If the white balance needs fixing then you use the white balance tool, of course. I suppose you, if you are “clever”, could fix the white balance using the channel mixer. But you would not do that, would you?
In which situations is the channel mixer be the ideal/natural tool to use?
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noob’s answer (trying hard 
):
1 - That sky contains blue, red and green
2 - When you reset the blue channel, it becomes green (see @s7habo’s previous post)
Forget the above for a moment.
If you have red and add blue, you get violet/magenta
If you add green to violet, you get orange.
So the green sky made of red+yellow became now violet+yellow, because red isn’t no longer red, since blue was added to it.
And violet + yellow gives orange.
This seem to be about primary and secondary colors, and I used as reference this color wheel.
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How can you fix something with the tool, that you don’t understand?
How do you know it’s good for anything if you don’t know what it does? 
I’m still waiting.
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@obe This is one of the best visual demonstrations I have seen…https://www.youtube.com/watch?v=zgTLw31PVNs
This is how i see the channel mixer for artistic color grading
example:
cyan + magenta = blu
original
what if we add cyan and magenta to blu?
add cyan and magenta in blue, add yellow to green
saturation
cinematic , similar to (teal / orange)
Questions:
- Why isn’t it red?
- How do you get it red so that green grass stays green?
Here is the original picture:
[/quote]
Here you have added yellow and red to blu, yellow + red= orange
Thanks Boris hopefully the transition to the DT channel mixer was obvious but your pic makes the point…I just thought the gentleman that is a retired teacher…explained and demonstrated it very well for anyone following the thread…thanks for the exclamation point…
I’m working on it… just work and life gets in the way of opensource contributions 
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Hi all - is there a way to split this thread into one for clarity and one for channel mixer? Great info in here to refer back to but people may not notice the channel mixer info due to the tread title.
Yes I can do that. Give me a few minutes.
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There you have it. Hopefully I picked the right topics… for topics that had mixed replies, e.g. some on filmic and some on channel mixer, I left them on the filmic thread. There were not that many.
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Great video and more in the same series….! I hope to see some practical examples on why/how to use the channel mixer……! Theory is great, but not so interesting if I’m not able to put it into practical use……
So, if your destination is the red channel then the blue slider adds/subtracts red from pixels based on the amount of blue in the pixel and the position of the blue slider. A little hard to grasp from text but easy to understand when watching the video! Thank you……
The destination can be r/g/b or h/s/l, when would you ever want to choose h/s/l as the destination?
Yes even when you know it is still a bit hard to work with at the start…for example adding green slider in the red channel makes it less green not more as it boosts the red overall so it can work in a way backwards at times and their
is basically the simple math behind it…its good to have the color info on the screen to see how it changed the overall pixel RBG values that helps me to keep track…Glad the video way helpful…I think I insulted Boris by including him…was just looping
him in and not suggesting he was lacking the knowledge…happy color mixing…
Mail](https://go.microsoft.com/fwlink/?LinkId=550986) for Windows 10
Hi’ @s7habo
This photo could be one of the problem photos you were asking for. The result of my edit is that the people are relatively ok but the cherry flowers are way to “heavy”. I would like “fluffy clouds of pink”. I hope you see what I am aiming at. Can this be achieved by channel mixer (and other tools)?
DSC_8833.NEF (31.1 MB)
Not so easy, because local contrast is very strong and the shadows are harsh.
But you can improve it a bit with channel mixer. Details later. Need to go now.
DSC_8833_01.NEF.xmp (9,9 KB)
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