Agx Look section: Unintuitive how it fits, more visual feedback might help

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Like others, I too watched Boris’ AgX video. It’s great stuff @s7habo, thanks for making it.

I got a bit surprised though when it started dealing with the Look section. It doesn’t change the curve?

Meanwhile, it has controls like power, slope, offset. So it does manipulate a curve. But not the one shown to us. So some other curve. But then… what curve? At least this is my inference of what is happening. Might be completely wrong, but that’s kinda the point.

Would it be possible to visualize this somehow? Another graph? Then intelligent questions like what’s the difference between the two and how they interact, what they are for compared to each other could arise in those trying to master this complex module. (Actually quite curious about these, feel free to answer them if you have the knowledge)

And for those who put in the time, the visual feedback could be helpful in their editing.

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No it doesn’t, the look section modifies things in display referred space, if I’m not mistaken. This is a simple slope/offset/power as found in other tools. Look at the histogram if you want to see how things change.

Please no. Enough space taken by graphs. Look at the image or the histogram.

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This is applied after the curve.
The curve itself is not affected by this.

Here is a Wikipedia article about it:

And here is a graphical representation of the parameters:

The offset parameter works a little differently in AgX. I tried to demonstrate this roughly in the video with GIMP.

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Yeah, based on this and the Gimp example, maybe the proposal to have another graph is overkill. Still I maintain that the current state is a bit confusing. Won’t be for me anymore, thanks to these answers, but maybe the feedback will still be useful for someone while it is work in progress.

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I think it should be clear when the module notes are presented as well…

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Somewhere I found documentation for AgX. Not sure where now because I just looked in the user guide and didn’t find it. It states the look section is displayed refer space and not the scene referred space.

As for the curve I don’t find it very informative and that is not a criticism. In filmic I felt I had to look at the curve a lot to make sure I wasn’t pushing sliders too far, but that is not my experience with AgX. But I am a novice to AgX and may be missing the importance of the curve.

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You get warnings for inversion of the curve that would nullify the toe and shoulder control but not for clipping I don’t think whereas in filmic the orange ends would show clipping…but I find the curve quite helpful to show how the toe and shoulders are shaped and the degree of contrast in the curve and then you just use the clipping indicators if you need them…

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That’s because the curve never clips like the one in filmic does (which never inverts, like the one in agx does). As I have said: different maths, curves and compromises.

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Not during editing, but if it helps, here is what the slope, offset and power controls of look do:

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Ya I was getting at the comment by Terry about the filmic curve. I assumed and I think it was a reference to fiddling to clear the orange clipping warnings in Filmic that was being talked about and taking care not to push…I feel like as you say because agx doesn’t clip and it therefore doesn’t constantly pop up these warnings as you adjust the DNR unless you invert it and so you can move the sliders more freely than you can with filmic without any warnings… otherwise I couldn’t reconcile what was offering more information in filmic vs agx …

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probably on github.

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dtdocs/content/module-reference/processing-modules/agx.md at agx · kofa73/dtdocs · GitHub (links with agx2.md are obsolete, the contents of that (documentation rewrite) have been used to replace the original documentation, because the rewrite is what people preferred.

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