Replicating black mist filters in darktable

I was thinking to a way to colorize the diffusion…

in this way the diffusion is bi-color red and cyan, red when a pixel become brighter but the diffusion is cyan when a pixel become darker

So I came up with this in gimp:

Let’s start with this image and what we want is a green diffusion

Duplicate two times the original image

the first step is to use the diffusion in the top layer on the green channel and set this layer to “lighten only” (the diffusion is green when a pixel becomes brighter)

the second step is to use the diffusion in the middle layer on the red and blu channels and set this layer to “darken only” (the diffusion is green when a pixel becomes darker)

and this is the resulting pure green diffusion

With this technique is possible to get directly red-green-blu-cyan-magenta and yellow diffusion.

Mixing red and yellow or red and green gives a nice warm diffusion filter

I just noticed that Ricoh added a HDF filter to their renowned GR III.

I experimented with the suggestions above again and found that they an easily replicate something very similar. Specifically, a not too wide radius span, 1st order diffusion, and edge threshold to taste.

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GAS! :smiley:

Fortunately for those with unmanaged GAS, Ricoh cannot keep up with the demand and apparently they go by lottery.

But again, this is something you can do just fine with a diffuse and sharpen preset.

Where’s the fun in that? :slight_smile:

I do like how japanese companies often use lottery instead of just letting scalpers take everything. You see it a lot in concerts as well.

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But you lose the built in ND filter in earlier versions, which seems a bigger thing?

I’ve never used the built in nd filter in my GR III. Not sure how much use I’d get out of the new filter either tho.

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Tbh, not sure I have! Just seemed like something that isn’t replicable in DT.

Looking back at 2024, I think that this topic had the largest impact on how I develop images in Darktable.

First, I started noticing the look associated with black mist (& friends) filters in movies. In contemporary cinematography, I find it nearly ubiquitous. If you know what to look for, it becomes challenging to find a cinema image without it.

Then I developed some styles that blunt the edges a bit for images I take, especially with backlight or specular highlights. I apply these selectively, often with an edge preserve threshold, and 50% opacity. Maybe 25% 1st and 2nd order speed, and one iteration, tweaked to taste, and maybe masked to exclude the main feature of the composition. Now my images look more “natural”, even my cheapo primes were too sharp.

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Also read through this thread again recently after watching the following nicely produced video that suggests using a quarter strength mist filter to try to blur the hard edges of clipped light sources in night photography.

Incidentally, I think he’s wrong on the slowest shutter speed you can use, given stabilised sensors and optics, though of course you might need higher speeds to freeze moving bodies.

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It is unfortunately overused. I think younger cinematographers have a romantic view of how older films used to look like, based on watching older scans/transfers.

Some films do grant the look, and even back then had these effects exaggerated by using old(er) lenses, vaseline on the lens, etc. A good example is Wong Kar Wai(Christopher Doyle as cinematographer).

But a lot did not, especially when shot on 35mm or larger. We only need to watch one of the recent scans of Lawrence of Arabia, as probably the most absurd example of pristine picture quality. Some modern films shot on film also look way more “pristine” than digitally degraded ones, such as Dunkirk, Tree of Life, A New World, Samsara, etc.

Hopefully this trend will slow down and it will be reserved for films that really need it and are enhanced by it. And I say this as someone who has glimmer glass stuck to his x100v :smiley:

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Indeed it is excellent for that day and age, but lenses have developed since then. Now extremely sharp lenses are well within the enthusiast price range, which creates a look that most people find straining. A tiny amount of “mist” tames that (of course there are other ways).

Indeed. One thing I love about night time street photos is the ability to blur people with 1/10s handheld shots using a stabilized body. Or if I have a mini tripod, any surface will do and I can do 2–5s exposures, which I find ideal for moving crowds, as it preserves some sense of people being there without making them recognizable.

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Can be used in the day, too:

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Yes, I just got a 100,000 ND filter last week and I find it pretty nice. Finally, long exposure in daytime!

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A recent UCM (Unintentional Camera Movement):

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In a lot of cases this can easily be fixed in Darktable by adding some exposure to specular highlights before diffusion. Eg here I masked the LED lights on our Christmas tree, which were clipped (I found the reconstructing in LCH gives the smoothest results), added +2EV, and then applied D&S.

This does not change the appearance of these highlights since sigmoid maps them to 1 anyway. But in the linear part of the pipeline, they add more “mist” with D&S.

This idea can be varied to taste, eg you can also color these lights to get a reddish haze, etc.

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Reminds me I still wish there was a practical way of creating halation in darktable.

Here’s halation from Filmbox.

I think there are multiple ways, eg

You apparently asked about this before, in what way is the solution unsatisfactory?

EDIT This is a simple halation simulation, using red channel blend mode (right):

Note that this part of the image is out of focus to start with. I guess I should stop before the whole picture turns into a gray/red blob :wink:

I have a vague memory of not succeeding. :smiley: I’ll have to try again. Check on @arctic’s history for some proper film halation simulation.