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

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?

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.

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.

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

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.

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Thanks

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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