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

[johnny-bit (Hubert Kowalski)]

Hello Dear Students and Teachers!

After recent influx of posts and posters saying in unison that they have problems with filmic I thought we need a place for learning. A place when people “having problems” learn how to solve them and a place where we can learn that those problems are, so we can improve our knowledge about real world usage. So this is this place!

If you sometimes think “filmic is too hard” or “I can’t achieve the look i want” or “it takes forever to get close to what i think i want and it isn’t what i want” (or similar) then this place is for you!

This is not a place for vagueness. If you have a problem you have to show it, you have to show your work and you have to expect further questions.

Before I start with rules, you have to understand that filmic rgb isn’t a drop in replacement for some other modules. It’s a part a framework designed around more correct ideas and current state of colour science, designed to be robust, correct, without weird hue shifts, undesirable, and side-effects and so on. This obviously doesn’t come cheap - the cost is different workflow and different approach that needs to be learned (on many cases re-learned). The payback however is great: no more weird skin tones that no healthy human should have, no more rat-piss sunsets, no more colour run-offs etc

Once you understand above and still have problems, we can help! Here are the rules:

1. We expect you to have read darktable 3.4 user manual - darktable 3.4 with emphasis on
   • darktable 3.4 user manual - editing an image: scene-referred workflow
   • darktable 3.4 user manual - the pixelpipe and module order
   • darktable 3.4 user manual - filmic rgb
     and all linked material
2. We expect a clearly defined problem, which means:
   1. You have to post a RAW with sample of problem
   2. you have to post the filmic edit that you attempted in darktable(xmp)
   3. you have to post the desired look (jpeg) created using different method (eg oocjpeg, basecurve-based edit, maybe even result from other apps) and/or clear description what and why you’re trying to achieve.
3. In case of generic “workflow” problems (as in “i can’t edit as fast”) or in conjunction with posting a sample RAW a screen cast showing your edit session is very well expected. There are multiple free video hosting/streaming services - use them for longer screen cast. Vague problems like “it’s not intuitive”, “it’s too complicated”, “I can’t work effectively” are not accepted - you have to show the problem you have.
4. Since sharing raws is expected, PlayRAW rules apply - uploaded images must have CC license. (However keep in mind this is darktable-only thread, meaning solutions will be in darktable and problems are from darktable)
5. No trolling, off-topic comments, emotional comments etc.

If you cannot follow above rules (eg. you can’t legally share RAW publicly and it’s the only one you have problems with) and still want to learn, then the most effective way is by private lesson with the teacher.

Now - please post your problems and the teachers will help you
Let’s have a great learning experience!

[Tim (Tim Cuthbertson)]

I intend to go through your Step 1 to generally help me get a better understanding. I suspect that doing so could help most of us a lot. Thank you for laying it out.

[MartinL]

Loving filmic but I have a question about ‘preserve chrominance’
It doesn’t require any examples as I need a bit of clarity on what is in the docs about it.
I generally set this to ‘no’ because I find the colours a little vivid even if I reduce mid-tone saturation for the other values

However in the docs it says about setting ‘preserve chrominance’ to ‘no’ as:

‘This value may yield seemingly “better” results than the other values, but it may negatively impact later parts of the pipeline, when it comes to global saturation, for example.’

The first part is true but what does it mean ‘negatively impact later parts of the pipeline’?
What effects will happen that I may need to be aware of?

[s7habo (Boris Hajdukovic)]

@MartinL

What effects will happen that I may need to be aware of?

This:

For comparison, oversaturated “rgb power norm”:

[MartinL]

Ok, thanks for that. I have never pushed saturation to such an extreme as that so have not really noticed.
Is it only saturation that is affected?

[s7habo (Boris Hajdukovic)]

I have exaggerated the saturation to show the color shift.

The problem is, as you can see, that the blue sky is not very saturated, which is good, but the disadvantage is that the orange tones are distorted.

@MartinL

Is it only saturation that is affected?

Depending on the algorithm, also to some extent the brightness. What works well is always dependent on the subject. Since there is no perfect solution, so there are different options that are best just tried. You can also test the different options later in the editing process to see what works best.

[MartinL]

Thanks again, I generally do flick the various options to see different effects for different subjects, I just wanted clarification on ‘negative impact’ as I haven’t really seen any

[johnny-bit (Hubert Kowalski)]

The preserve chrominance option as the name suggests preserves chrominance in one of several ways. The chrominance preservation avoids hue shifts, over/under saturation of certain colours and prevents gamut escapes.
The “no” option for preserve chrominance isn’t “better” (to the contrary) however can be used in some situations. Similarly every other norm isn’t better from one another. “RGB power norm” is usually good compromise in many situations.
Personally I believe that the only way to know in practice which norm to choose is to test with your own photos and see what “works”. For my photos most used option is “rgb power norm”. the “no” option is most used when dealing with weird sunrise/set photos as “no” tends to desaturate highlights better.

[MartinL]

Thanks

[s7habo (Boris Hajdukovic)]

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:

Using filmic in darktable: photos with narrow dynamic range.

Optimal dynamic range photos:

Using filmic in darktable: photos with normal dynamic range.

High dynamic range photos:

Using filmic in darktable: photos with high dynamic range.

[rgo (Rafa García)]

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

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

[priort (Todd Prior)]

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)

[nish]

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?

[priort (Todd Prior)]

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…

Clarity in darktable

The images you posted all have two instances of the module. Did you use the default settings for the first instance?

[s7habo (Boris Hajdukovic)]

@nish

What does your “Local Contrast” quick preset do?

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

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.

@nish

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

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.

[s7habo (Boris Hajdukovic)]

@priort

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…

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.

[pass712]

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

[s7habo (Boris Hajdukovic)]

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

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.

[s7habo (Boris Hajdukovic)]

@pass712

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 ?

Ok, let’s see…

1. Without:

2. Red lighter blue darker:

3. 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?