Waveform histogram

Hi All,
looking to Darktable saw there’s an histogram form I didn’t see ever or often.
That’s the waveform


Would be of some utility in RT, too? Or would be too much complex to implement??



As to not seeing it ever or often - it’s very common in video-oriented products.

As to implementing it in RT - interesting idea, not sure how difficult it would be.

This comes up once in a while and I usually add the comment or two that I would absolutely love more types of visualization of the data. I have also seen some inventive variations of the standard waveforms and vectorscopes.

@dafrasaga What is your particular use case for a waveform? What kind are you looking for?

Hi, I saw it in a tutorial where It is useful for ETTR exposition, but I do not understand more :frowning:

ETTR is something you figure out while taking the photo.

1 Like

The main benefit of the waveform display is that it not only lets you see that you’re clipping a channel in the histogram, but to give you an idea of WHERE in your image (at least in the horizontal plane) you are clipping.

An alternative to this is a mix of histogram and “zebras” or other methods of over/underexposure highlighting that change the color of a pixel if it is brighter or darker than a given threshold.

1 Like

@hanatos showed me the Waveform histogram at lgm 2019, and it’s really cool. Maybe we can steal the code :wink:


It is a steal for sure. :wink:

Well, that balances over the time :wink:


Representing all Canadians.

Ok, I know it… in fact it was obscure because waveform histogram in post production would done useful for ETTR.

In RT , when I want to know where is clipping I use, as you, the clipping indicator and for what channel is clipped the preview channel button at the top of the preview window…therefore… what is the utility of the waveform histogram for that… ?

For reference: https://github.com/Beep6581/RawTherapee/issues/4763


Thanks for the information

i doubt you need to steal these two lines of code. probably faster to type your own version than to copy/paste + fixup… :


WOW!! waveform is in dev @Lawrence37 Thanks a lot !! :+1:


Now my task will be to understand what it indicates :sweat_smile:

1 Like

The horizontal axis in the waveform histogram corresponds to the horiziontal axis of your image. Means you can see where for example highlights are clipped


Thanks! Now as you say it … I also had a look at the video linked a bit above. So the white bar on top indicates “all channels clipped”.
And big thanks for implementing all kind of useful tools!