Let's learn Filmic RGB! Your one stop shop to understanding filmic-based approach to edits!

To introduce the topic, I decided to demonstrate how I typically use filmc in my everyday use of darktable.

For me, filmic is always embedded in the processing steps and serves mainly as an aid in dealing with different dynamic ranges of photos one is confronted with as a photographer.

Accordingly, I roughly divide photos into three different groups:

Low dynamic range photos - low contrast, “flat” looking photos with not much difference between shadows and highlights. Filmic can here extend the range and increase contrast.

Photos with “optimal” dynamic range - Well-lit, high-contrast photos that don’t need much processing. For this the default setting of filmic is sufficient and I don’t have to adjust it during processing.

Photos with very high dynamic range, which are mostly underexposed during shooting to avoid overexposure. Overexposed photos (if they are not of particular importance) end up in my trash.

High dynamic range photos can be very challenging to process because you don’t have a lot of room to maneuver with exposure compensation and you always have to watch out for the highlights. Filmic is very useful here for compressing the dynamic range, giving you much more flexibility to emphasize the main subject without risking image artifacts.

So, my approach is that the brightness of the photo and the dynamic range is always subordinate to the subject. This means that I don’t have to use the full dynamic range if it’s not necessary.

And what the subject is, I decide as a photographer and not some algorithm that mathematically balances the dynamic range evenly!

So now for each group a pair of examples. Each time before I start processing, I will move the mouse to the subject I want to emphasize. I will also point to the histogram. I will not only focus on the filmic, but embed it in the processing so that you can compare the final result with the unprocessed photo.

Low dynamic range photos:

Optimal dynamic range photos:

High dynamic range photos:

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Thanks @s7habo for taking the trouble of recording these screencasts, the examples are indeed very valuable. :clap:t2::clap:t2::clap:t2:

[off-topic] First time I use “to take the trouble” expression, I hope it’s correct the usage :grimacing:

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As noted by @s7habo the subject matter may dictate what norm works…I noticed recently when I took a quick picture on my phone that there can be some unexpected things. I am making some new shelves for my paint etc and I looked at the array of cans etc and thought what a nice array of color to experiment with.

Zooming in to 200 % looking at the milk bag of the attached image note the blue color. In some modes it is preserved and others it is rendered as black…this could be a function of what modules I have used or gamut or some other thing but still it shows what can happen.

Preservation at no


max RGB

luminance

Power norm

Euclidean

After noticing this I found that this was introduced by setting I had made in the contrast eq and the modes handled it.PXL_20210217_060754661.dng.xmp (11.0 KB)PXL_20210217_060754661.dng (13.6 MB)

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A lot conveyed in so few words… thank you for the great videos.

I had a few questions:

  • What does your “Local Contrast” quick preset do?

  • In the low dynamic range video, you use the Filmic scaling option instead of adjusting White/Black relative exposures, any reason for this?

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I think he is using one of his clarity presets…now likely with reverse multiply or some version of that…there was a nice discussion here a while back…

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This is simply stronger local contrast limited to mid gray range by parametric mask:

LoC

It works in most cases without any additional adjustment (quick) and is mainly used to restore the local contrast lost by filmic’s dynamic range compression. But I don’t always have to use it.

It widens or narrows the dynamic range symmetrically. You can work with it quickly and, if necessary, use other two sliders to readjust it. I’ve mainly used it to widen the dynamic range, or in rare cases when the other two controls aren’t enough to compress, you can use it to compress even more.

For the narrowing of the dynamic range, I use the first two sliders first, because you can influence the areas that should be compressed (shadows or highlights) more directly for the corresponding photo.

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This is my favorite preset but I didn’t want to distract too much from the theme in the above examples so I used a simpler version. :wink:

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Thanks for your videos, very inspiring!

One “tweak” you used in almost all examples was to use color calibration and then in brightness you pulled up the red and reduced the blue. What is the reason for this ?

Greets
Jürgen

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For the three sliders in the first Filmic module tab I have a mnemonic :grinning:

Think about the “scene” tab as about a bandoneon:

You can pull or push only (or first) the left hand (white relative exposure) or right hand (black relative exposure) or or both simultaneously (dynamic range scaling) and then left or right again.

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Ok, let’s see…

  1. Without:

  1. Red lighter blue darker:

  1. Blue lighter red darker:

Prize question 1: What is the difference?

Prize question 2: What did I want to direct the viewers to with version 2 and to what with version 3? :thinking:

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I have to confess, Filmic RGB has not been easy for me. I like the capabilities it offers, but I also often struggle with it, particularly with regards to hue changes:


DSCF6544.RAF (32.1 MB) DSCF6544.RAF.xmp CC-BY-NC-SA

This is a simple enough picture of a fire, and the remnants of our “Christmas Tree”. Most of the fire is clipped in one or more channels.

My problem is, as soon as I enable some variant of “preserve chrominance”, this happens:


RGB euclidean norm

luminance Y

max RGB

RGB power norm

Furthermore, I tried to use “middle tone saturation” as a general saturation control, and do not like the way it pushes highlights towards white:


filmic RGB middle tone saturation +10%

color balance output saturation 110%

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Another thing I find confusing about filmic RGB:

trees
_DSF1845.RAF (21.3 MB)
_DSF1845.RAF.xmp
CC-BY-SA-NC

This image has bright and dark parts. And I like to adjust the darkness of the dark parts and the brightness of the bright parts with filmic’s “black relative exposure” and “white relative exposure”. However, while “black relative exposure” mostly changes the darkness of dark parts, “white relative exposure” changes both bright and dark parts.

For example, here is the same picture with “black relative exposure” lowered by two EV:
lowered shadows
Notice how the highlights look very similar to before (86.46 vs 86.85 L* on the bright bark on the left) but shadows changed visibly (18.72 vs 16.13 L* on the dark tree trunk in the top left quadrant)

And here is the same picture with “white relative exposure” increased by two EV (and black relative exposure reset):
raised highlights
Highlights are lowered (77.35 vs 86.85), but crucially, shadows are now much lighter (22.15 vs 16.13).

There are probably sound technical reasons for this, but it leads to “white relative exposure” acting more like an overall enlargement of dynamic range than a localized adjustment of (mostly) highlights. “black relative exposure” however acts mostly on shadows.

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Lastly, I often like to adjust my contrast using the “contrast” slider in filmic RGB.

default contrast

Inevitably, this leads to part of the transform becoming orange, indicating lightness reversals.

increased contrast

Thus I lower “latitude” until the orange goes away.

reduced latitude

However, the latitude adjustment requires no thought, and is a purely mechanical response to the orange in the curve. Frankly, it should be automated. Perhaps by introducing a “contrast priority” checkbox next to the latitude that auto-adjusts latitude to the highest non-reversing value. Or perhaps with a change to the underlying spline that “tightens the bend” sufficiently to fix the reversals.

But more than an inconvenience to my editing, it makes a one-dimensional contrast adjustment into an iterative procedure of balancing two variables: Increasing “contrast” increases punch in the image, decreasing “latitude” decreases punch. So what should be a “drag the slider until contrast looks pleasing”, is in reality “drag the slider until contrast looks pleasing, then drag latitude until it is no longer orange, then back to contrast, then back to latitude, etc.”.


Despite these three negative posts about filmic RGB, I want to state clearly that I like filmic and the scene-referred workflow a lot. It is a fantastic module, and produces outstanding results!

I am merely pointing out gotchas (and workarounds!) I discovered in my work that probably trip up other people as well.

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Thank you for very useful workflow videos. Unfortunately, they have no tone recording, am I right? Your clipping indication is active as I always do, too. Which clipping preview mode do you select, “any RGB channel”?

Latitude/contrast aren’t the only way to fix these issues though. For example, you can also use the “shadows/highlights balance” as well as a number of items in the display and options tabs. So how do you decide which way to automate?

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I will be careful here and separate it a bit: This is not about the difficulties with Filmic but primarily about dealing with a cardinal mistake of the photographer. The highlights are overexposed and in these areas there is no information about two important color channels red and green. The darktable now has to make up for this and reconstruct the missing data. This is an almost impossible task and it is no wonder that one struggles with it.

And just to clarify - when I say “cardinal mistake of the photographer” I don’t mean you directly, but anyone who photographs intensively, including me, regardless of skill. Such things happen all the time.

That being said, does this look any better to you?

DSCF6544.RAF.xmp (7,7 KB)

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Hi @Redbrook, and welcome to Forum!

Yes.

Yes.

Indeed.

  • “White relative exposure” changes: White- and black-point and midtone-contrast by shifting
  • “Black relative exposure” changes: Blackpoint, midtone-contrast slightly by shifting, highlight contrast(slightly)
  • “contrast” changes: midtone-contrast, blackpoint and whitepoint (slightly)
  • “hardness” changes: shadow/dark-, midtone-, highlight-contrast and blackpoint (slightly)
  • “Latitude” changes: shadow/dark-, midtone-(slightly) and highlight-contrast
  • “shadow/highlight balance” changes: shadow/dark-, midtone- and highlight-contrast, blackpoint(slightly)

This is not an exhaustive list, meaning: I did not try all combinations of parameters, nor all parameters, but only the quickly accessible ones. Also, as you mentioned, certain parameter combinations give inversions and clipped values. Some of these can be mitigated by switching to cubic splines.
To ‘learn’ the theory behind the sliders I suggest practicing a lot as well as looking at the resulting curves in @jandren 's tonecurve-explorer https://share.streamlit.io/jandren/tone-curve-explorer. Or, as others have suggested, make working presents and use them without fine tuning them too much after application.

EDIT: I should clarify: the “by shifting” expression used above means that it shifts the contrast slope that you have either up or down, effectively changing the contrast in the midtones.

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I think this encapsulates my struggles with filmic, and I can see hundreds of Lightroom refugees running away right now saying “I just want to set my black and white point” (which is almost instantaneous in Lr by double clicking the Black and White sliders respectively). There are just so many ways to adjust tonal values and countless combinations within filmic and I find it hard to “remember” what the best or my preferred ways are to go about setting the dynamic range I want. Note that this is not a criticism of the module, because such fine control is truly amazing, but I personally share some of @bastibe’s struggles.

One might expect that the white and black relative exposures should work the same way, but on opposite sides of the tone curve. But as @PhotoPhysicsGuy points out, this is not the case. Hence, I juggle between the sliders to set my black and white points and to get the look I want. I’m sure this is user error at not understanding the module properly, but I feel it’s a common struggle with less advanced users. So, to be more specific in line with the rules of this thread, what is the expected way to set your black and white points if you’re trying to maximize dynamic range (e.g. max black and white without clipping)? Is it even best done in filmic?

Adjusting contrast has also been one area of confusion for me. I find that the spline almost immediately registers an inversion when I adjust contrast in the Look tab, which means I almost immediately adjust the latitude to undo this inversion. This means I sometimes go straight to color balance to adjust contrast there instead. And maybe that’s not a problem. Is there any expert opinion on the “best” place to adjust contrast? Or is this simply personal preference?

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I think you are right and others can weigh in…but filmic sort of removes local contrast and trying to recover it with contrast in filmic might compromise other aspects of your filmic application to the image so I think using other means to achieve contrast is the way to go…I am sure others can weigh in but I think maybe people trying to adjust and achieve contrast using that slider in filmic might be some of the issues people are having…

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