Filmic RGB shadows

Software darktable
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#1

Hello,
I am fighting with Filmic more than a year and still can’t get the same results like with simple Curve in RawTherapee. I would like to have an universal style in Darktable for my Panasonic Lumix LX100 to export RAW into JPG (using command line).

See my example, with the same level of brightened shadows on the car door, I get very washed image using Filmic in DT 3.4.

RT vs DT
RT vs DT1202×945 274 KB

And vice versa, having the same contrast on the mountain, results in very dark shadows on the car.

How to control shadows with Filmic, I tried all sliders but always worse than editing the curve.

Thanks for help.
Peter

#2

Have you tried turning on the local contrast module?

#3

I don’t think this will work well… If you want automation, then RawTherapee’s auto match tone curve with a few other modules is probably a better way to go.

#4

You are probably right, but I am not able to get the same result even with manual Filmic adjustments in DT GUI.

And yes, I tried Local contrast, but this is a minor difference for this issue with shadows and overall picture dynamic.

#5

See https://discuss.pixls.us/t/darktables-filmic-faq/20138: Would it be possible to auto-set filmic ?

If you share the raw (with a permissive CC licence), maybe people can help.
Until then: this looks like an image with deep shadows (dark interiors of a car) and bright highlights (sun-lit snow), so contrast tone EQ may come useful to compress the dynamic range before you apply a curve. But if you say RawTherapee handled it with a simple curve, most probably you can find a curve (base curve, tone curve, RGB curve, a curve created using contrast tone EQ without detail preservation, filmic) that can do the same.

#6

I’m not a darktable user only an occasional dabbler but wouldn’t the tone equaliser be useful in this situation? Certainly doesn’t help with the automation however.

Things might have evolved but for me one of the main challenges while testing filmic is how to get good images when an important part of the frame will be a bit dark. Perhaps I’m overstating this but a lot of the filmic effort has been about taming highlights and having contrast in midtones. I’ve struggled with shots that diverge from this model.

The tone equaliser seems to be the tool to tame the shadows a bit.

#7

Yes, of course or rgb curve or …
There’re several modules to achieve this faster and easier. It doesn’t make sense to expect filmic to be a jack of all trades

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#8

In what I find, filmic is for mapping overal tone, and get hdr into sdr.

I also notice that the shadows / blacks can be really dark.

In the first tab, raise black level or in the output tab raise the black mapping. If this yields an image that is too flat, use local contrast to get some subtle pop back.

But if it doesn’t yield what you want, it’s perfectly fine to use something like ‘shadows and highlights’ module or the ‘tone equalizer’ after filmic.

'Shadows and highlights ’ with the default settings but highlights turned to 0 is a good simple ‘raise shadow detail’ method. Tone equalizer is awesome and simple to get more control.

But filmic and ‘auto’ is not something that clicks in my head. You need to correct the exposure anyway and I see no auto way of doing that in a way I would trust it.

The defaults in filmic are very sensible and work for a lot of images… If your exposure is right. If you feel you always need to raise shadows, add the sh&hl module like I described to your preset.

… But I can’t imagine you always want to raise shadows…

#9

This module should be used with extreme caution, as it halos quickly and the effect is not nice.

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#10

The thing is that generally speaking with a contemporary digital camera. To capture “hdr” you have to under expose to avoid clipping. This means you later have to raise shadows. Filmic does fine when you raise shadows by increasing exposure so that the area where you need contrast becomes a mid tone.

So for portraiture where you want a well exposed face for instance this works well. For many types of images you may need a different distribution of contrast. For me I frequently need contrast in the darker tones whilst accepting a bit of a loss in mid tones and highlights. So when working with curves I tend to have a tiny toe then immediately a steepish incline then the curve makes a large soft arc to white. The above image is a mild version of this. Manipulating tones this way is surprisingly difficult with filmic because it’s made with certain assumptions in mind.

It’s become easier and easier to work around it and now it’s getting pretty good. I still feel however that you’re working against filmic when trying to achieve something like that.

#11

@P_Cherry could you share the raw file?

#12

Sounds like raising exposure till the shadow part looks OK, the enable filmic and deal with the white slider.

The did do landscape style shots with filmic, specially for dawn situations with the sun creeping through creating a very wide dynamic range. Filmic does well for me there. Just don’t be afraid to slam the exposure up before filmic. Or turn the midpoint control back on and raise that to get more room for shadow - content.

But… The important thing about my post was that filmic is a tool to map hdr to sdr. Or at least map a dynamic range into another (smaller) dynamic range.

Its not a one-stop-shop-does-it-all module, it’s OK to grab tools after it to modify the result. After filmic you are in display-space so basically every module is fair game.

And of course if it doesn’t work for you don’t use it :).

For me working with curves on the raw data doesn’t seem ‘right’ or logical. You can’t do curves on data that sits outside your curve. So you first have to bring data in to sit between the 0.0 and the 1.0 point… There’s filmic for that. And you might have to define how far down and how far up your (usable) data sits in the raw file… There’s filmic for that.

Of course, filmic is in a simple way a s-curve editor,with color mapping and support for values below 0.0 and above 1.0.
If you often used to modify the base curve in a way that it doesn’t look like a s-curve or simple gamma curve… Filmic (alone) isn’t going to help you.

#13

Yup, I just think this will need to be repeated. Figuring out when, typically, filmic is counterproductive is useful I think. Just to say again that filmic is improving and it seems to handle more and more cases with every release.

#14

Peter don’t confuse filmic with the process in RT…you likely have automatch tone curves on …well maybe and that creates a tone curve with an attempt to match the histogram in the jpg preview so the two will not ever be equivalent. Filmic can sometimes nail an image on its own but it is designed as a tonemapper to handle HDR and bring everything into your display range so you will usually need contrast eq , color balance and often tone eq as 3 or 4 combined modules to finish your image. For a shot like yours I often add a linear tone curve and blend it in subtract at 10-25% opacity. That will offer some dehaze and nice controlled contrast boost. Given your subject matter I suggest you watch a couple of these videos to get the idea of a DT workflow…nice landscape edits using the modern version of DT and tools… https://www.youtube.com/channel/UCjQYrYEwWGqxvofPye16tTQ/videos

#15

Thank you guys for a lot of insight. I would rather not to share raw now because there is my family on it (they are not ugly but better not to have private pics in forum:) Maybe I will try to find a similar dynamic one without people as next example.

My goal is to have DT style which can do the similar thing my camera is automatically doing when shooting RAW and saving JPG in parallel. Sure I can do Tone EQ later manually.

But I thought I can replace curve by Filmic with even better results using Display based workflow instead of Scene referred workflow.

#16

You can use filmic with a display referred pipeline ording if you want, but I doubt it will give you better results than using it with the scene-referred workflow.

#17

Maybe the closest thing you will find in DT is running DT chart. This requires a color card . Then you match your raw and jpg. You will get a style with a tone curve and a LUT. With filmic you will always need to tweak a bit and its not going to be your automatic solution in most cases just a good tonal starting point for raw development. There are several topics on the forum about raw and jpg matching…if you want to read some spirited back and forth then search for them.

#18

Problem with DT chart is that the tone curve is only valid when you shoot under the same conditions and same exposure settings as those when you shot the color chart.

You can use a tone curve in a scene-referred pipeline, but before the tone curve you need to use exposure module to bring the white point down into the [0,1] range, and then set your mid-grey point by altering the shape of the tone curve. It’s do-able, but fiddly, and the whole point of filmic was to parameterise the curve to give you a simple and repeatable way to set up the shape properly.

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#19

I understand but this is one of those make it look like the jpg questions so that is what I provided. I actually have decent results doing this sort of thing but I modified a little bit Pascals colormatch script to work with my colorchecker and it creates an icc from a raw jpg combo. It does a nice job using argyll to create the icc file. I am not sure on the math of how he blends the files to get the common ti3 data from the color checker but it does create a nice profile. https://github.com/pmjdebruijn/colormatch

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#20

What I do:
Increase exposure module 1-2 steps
Activate filmic RGB and get back the highlights
Activate Local contrast and am using Multiply at 50%

Example in Swedish below, but you will recognize the modules.