Darktable Tricks

When denoising high ISO pictures, I found that doing the following is sometimes quite efficient:
Use the bilateral denoise with radius set to the maximum, red and blue to the maximum (or close) and green to the minimum.
The red and blue channels are frequently more noisy than the green one, and using this parameters allow to smooth them without losing too much details.
Please note that this technique is inefficient if any denoising smooths the color before this module in the pipeline. For example, if you use denoise profile with wavelet in “color” mode, this technique will not give proper result.
Thus, when I use it, I smooth color noise later in the pipeline, with a second bilateral denoise module in “color” mode

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Thank you Andreas, I forgot to add that one, yes I use that also—I saved it as a style. Another denoise triplet I saved as a style is:

  1. Lowpass 1 - Radius 15, Gaussian, Contrast 0.93, Brightness 0.03, Saturation 1.0, Blend uniformly, Blend Mode Lab a-channel, Opacity 100%
  2. Lowpass 2 - Radius 15, Gaussian, Contrast 0.93, Brightness 0.03, Saturation 1.0, Blend uniformly, Blend Mode Lab b-channel, Opacity 100%
  3. Equalizer - stock preset ‘denoise luma only,’ mix 1.0

Not sure where I got this, probably Harry again, but I named this style ‘Denoise Gentle’ as it removes some of the noise without turning the image into a watercolor. Play with it, I get good results, sometimes I increase or reduce the Equalizer mix to fine tune.

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Thx - I love this and am learning so much!

The site https://www.multimedia4linux.de/ contains a lot of darktable material - tutorials, videos, plugins. Most of the texts are in German.

nice! i’m thinking we should maybe ship some of those with stock dt. presets can be a good starting point, source of inspiration and hands-on documentation.

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One of Harry D’s presets that I frequently use. It does wonders for opening-up and providing texture to the deepest shadows. A very important tool in my processing.
Tone Mapping: Compression=1.66, Spacial=6%, Para Mask on ‘g’ with settings= 0 0 0 8 and Normal blend.

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So many useful tricks here. Keep them coming!

Denoising ISO1600 on MFT (Probably ISO6400 on FF)

  • Hot Pixels - threshold 0.01 - strength 0.7

  • Demosaic method amaze - color smoothing five times - match greens disabled

    1. Denoise Profiled - wavelets - strength 0.250 - blend mode color
      parametric mask on L channel 0 0 0 15
    1. Denoise Profiled - non local means - patch size 4 - strength 1.0 - blend mode average
      parametric mask on L channel 0 0 0 15

This gives nice analog looking grain.

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Thanks for sharing, David. Yes, it does do wonders! :clap:

I do my rating/culling as chris describes. Works fine and fast. RAW files show the JPG preview if no processing was done so that’s fast.

I setup this Tone Mapping preset, but I’m not seeing much changes in the dark areas. I do confirm the mask is picking the very darkest parts of the picture. Maybe its because I’m working with jpg?

One more:

soft light illumination with bloom module.

this is the starting point:

I would like to draw even more attention to dimly lit houses on the horizon

So first I need to brighten up this local area (exposure module with drown mask):

Now I’m activating “bloom” module in “effects tab”, increasing size to 70% reducing threshold to about 25% and increasing strength to 70%.
blend - uniformly
blend mode - multiply:

Here is before and after:

One more before and after:

The values of bloom module, which I mentioned above, are of course adapted to the corresponding motif. Accordingly, they serve only as an orientation.
It is important to first illuminate the area of the image that you want to emphasize according to your own imagination and “bloom” module makes sure that this emphasization is smooth.

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Hi Alan;

    This preset will only effect the very darkest elements of your image .. (those values between 0 to 8 on the gray scale of 100). If you click on the mask display you will see exactly which area is being changed. The changes are also progressive so that the darker the element, the greater the change.

    It is possible to change the 8 value to a higher number so as to effect a wider shadow scale. Tone Mapping can be a very aggressive function if used over wider areas so you should understand it better and use it with caution .... it is not a quick fix for underexposed shots.

    If you are having under/over exposed problems sometimes using 'fusion' processing (in the base curve module) can assist.

    darktable is designed primarily to be used with RAW camera data and not JPEG files that are already preprocessed and compressed within the camera. The use of the Tone Mapper on JPEG files may well not produce the designed results. If you are serious about getting the very best out of your personal skills and the camera's capability, you should really work in the RAW format.

Cheers;

David

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Hi Alan;

This preset will only effect the very darkest elements of your image … (those values between 0 to 8 on the gray scale of 100). If you click on the mask display you will see exactly which area is being changed. The changes are also progressive so that the darker the element, the greater the change.

It is possible to change the 8 value to a higher number so as to effect a wider shadow scale. Tone Mapping can be a very aggressive function if used over wider areas so you should understand it better and use it with caution … it is not a quick fix for underexposed shots.

If you are having under/over exposed problems sometimes using ‘fusion’ processing (in the base curve module) can assist.

darktable is designed primarily to be used with RAW camera data and not JPEG files that are already preprocessed and compressed within the camera. The use of the Tone Mapper on JPEG files may well not produce the designed results. If you are serious about getting the very best out of your personal skills and the camera’s capability, you should really work in the RAW format.

Cheers;

David

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Thank you! I love the softer vignetting. Here is my quickie attempt, before, after the technique, and fully edited (including applying Norman’s denoise trick above). IMG_3461IMG_3461_01IMG_3461_02IMG_3461.cr2.xmp (12.0 KB)

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My current favorite trick to get postcard landscapes is to

  1. Use three exposures in base curve sparingly to get a bit more detail if there is a lot of dynamic range

  2. Apply a gentle base curve like the Leica preset because the next step adds contrast

  3. Use the filmic tonemap operator with maxed or high detail. Set blend mode to multiply and reduce opacity to taste.

  4. Enjoy very saturated postcard look.

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Thanks Cran!
Here is my attempt at using your technique:

IMG_3462.cr2.xmp (8.4 KB)

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Here’s another one of Harry Durgin’s tricks I must have missed until the third viewing:

Using a parametric mask with spot removal module. With a high contrast border, create the spot removal area and adjust the parametric sliders to restore a portion of the underlying image. See Harry’s example in this vid at about 20:20 minute marker.

https://www.youtube.com/watch?v=JF5CFQPgidk

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I’m not sure why the fence posts became green but the sky looks like it is supposed to.

I use a Mixture of Exposure and Color Zone to even out Fade in skies.

Settings (Masking should be identical for both the Exposure and Color Zone modules)
image
image

Use the “H” parametric mask to select only blue sky region, and not mountains, trees, etc…

Make sure to change the “L” parametric mask to be subtractive, then use the eye dropper tool to help you set up you 100% and 0% sliders as shown above.

For me, typical exposure adjustment is somewhere between -0.05 and -0.2
In the Color Zones module I just boost the blue’s saturation (with the same mask and parametric masks applied as were used in exposure module) until the regions appear to have similar hue/saturation.

Using “Small” view can help to see the Fade more pronounced.

Example below is a merge that came from enfuse.
Before:

After:

Mask:

This can really save images that get “Halos” from HDR or enfuse.

Hope this helps others.

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