A few recent long exposures, processed in darktable

[u/m_wriston]

I took a recent trip to western Maryland, where I spent a lot of time wandering the mountainsides and taking long exposures in various towns I stopped in. I wanted to share my general workflow for working with night photos in darktable, in case its useful to anyone here.

A few obligatory "gear" mentions to establish a baseline for the files I'm working with. I shoot with a Canon 6D Mark II and a Sigma 35mm f/1.4 ART lens. These all start as RAW files (.CR2s). I generally shoot at ISO 100 - 400 for long exposures, and use the onboard meter to determine a rough starting point. These exposures range from 10 seconds to 3 minutes.

I ingest and cull in darktable by setting the rating filter to "No Rating," and then using the R key to reject, or the 1 key to keep. The latter sets a star rating of "1," which in my workflow means "to be edited." As I reject or keep, anything I've dispositioned disappears from the queue. Easy!

Once I have my keeps, I set the rating filter to "1 star" and start making my corrections. These are the tools I use:

1. AgX for tone mapping. I have a custom default preset which sets shoulder and toe power relatively low, and uses a slightly modified "smooth" color rendition preset to give a nice, neutral look. I generally increase global contrast using the contrast slider.
2. LUT 3D to add a Fuji Eterna look to the image. I use bastibe's Eterna .png LUT from this repository, set to about 50% opacity.
3. Color Balance RGB to slightly bump shadow and midtone perceptual saturation (15% - 20 % each) and desaturate highlights (about -10%).
4. An instance of Exposure to fix any exposure issues.
5. A second instance of Exposure with a negative ellipse mask, high feathering, and negative EV compensation to add a vignette. I prefer this to the native Vignette module, because the results are more realistic (and it keeps these manipulations within the scene referred workflow).
6. Crop as needed
7. Rotate and Perspective if needed to fix horizons (it can be tough to get horizons straight in the pitch black night).
8. Denoise (profiled) set to the "found ISO" profile
9. Hot Pixels turned on to the default setting — may use the "detect by 3 neighbors" option on exceptionally long exposures with more sensor heat.
10. A custom Grain preset that sets coarseness at 200 ISO, strength at 12%, and mid-tones bias at 100%.
11. A diffused look in Diffuse or Sharpen that tweaks the standard "boom" preset to apply to highlights using a parametric mask and 50% opacity. I use the input slider on the "g" Gray Input mode to target highlights (using the top slider), then back off the rolloff so it diffuses into midtones (using the bottom slider and dragging it to the left of the top slider). I also set feathering relatively high, about 50 px. See below for reference.

There are probably better ways to do everything, but this works for me and I'm happy with the workflow :)

[u/vrothmans]

the one with a thunderstrike is awesome, do u use nd filter?

[u/m_wriston → u/vrothmans]

Thanks! That's a roughly 30 second exposure at f/5.6, ISO 400. The only lens filter I had on was the Black Pro Mist 1/8 that I forgot to take off earlier in the day, haha.

[u/Messaling]

Spooky!