I’ve recently discovered the waveform histogram and I find it much easier to set the exposure. However I must admit I know nothing else I could use it for or even if I’m using it correctly (I just adjust the exposure until the waves (?) almost reach the top. Are there other uses for it? I think its been around in darktable for sometime but theres very little information on it.
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you mean like this?
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Thanks, I have seen this but I was wondering if people had other uses for it in their workflow.
It contains spatial info so you could see the dynamic range and distribution of colours along the x-axis. The histogram doesn’t. I think dt only has one type of waveform. Typically, video monitors and editors provide more ways to represent the data such as adding guidelines, showing percentages or showing channels other than RGB. I recommend reading the docs or tutorials of such apps.
I find it very useful for keeping control over what happens locally on the image.
Here is an example. You can see brightness and color distribution very precisely:
You can see very clearly from the waveform that the wall illuminated by the sun stands out in brightness from the rest of the picture. You can also clearly see that the red channel in this area is at the limit of the dynamic range:
Since I can see exactly what the spatial distribution and the relationship between brightness and colours looks like, I can specifically compensate for this.
In this case I can use channel mixers to transfer a part of the blue channel to the red channel and at the same time reduce the red channel. I’m using lightness blend mode to affect the brightness only.
Now the brightness between the blue sky and the wall of the house is balanced:
Here’s Waveform before and after:
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Moinchen!
In this case I can use channel mixers to transfer
a part of the blue channel to the red channel
and at the same time reduce the red channel.
Splendid idea! Could this idea form the basis for another of your tutorials??? 
MfG
Claes in Lund, Schweden
Yes, but I need to find some nice samples first.
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Yet another example of “practical” use of the channel mixer………
. If we collect a number of examples like this we could update/expand the user manuals section on channel mixer. Presently the text is of very little use (if you are not looking for converting images to BW) and does not explain the potential of this tool.
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