[RCC] M42 Orion nebula - Photoshop

Hello everyone,

I just got my first monochrome cam last week and while not being equipped to shoot in cold nights for the moment, I decided to spend as much time as possible for editing. My purpose is to find a proper editing process that would 1) Avoid losing as much data as possible 2) Keep a natural feeling 3) Keep interesting colors that match well together.

This is only a stack of x1 H, x1 S, x1 O of 180s each, with dark frames, so I am NOT looking for suggestions regarding the poor quality of the picture/blurriness. Initially, it was meant to be a shooting test, not intended to be processed. I'm looking for your input for the other aspects: regarding your processing suggestions, color choices, what you'd avoid, what you'd change.

I used AstroEd Youtube videos as a starting point for editing. In his videos, he was using the channel mixer to even his colors, he boosted the lowest channels colors to match to the level of the channel with the most luminosity. In my case, I saw a huge loss of details in the light pixels trying to use the channel mixer to boost colors, in the core of M42. This is the reason I used levels to adjust. Maybe it works well if the data is pretty well flattened instead? Orion is also probably pretty rough for the variations of light, might not be a good subject for this. Would love to hear anyone's thoughts on using the channel mixer.


Here's my Photoshop editing process below, I tried to keep it on adjustment layers as much as possible, so I could always go back and change a little thing if needed. Especially since I'm still trying to find my colors.

After doing a basic Arcsin curve to the stacked picture of each filter:

First file:

1. Combine SHO shots to the RGB channels in a new file + align them + crop edges
2. Create a layer threshold, edit the threshold to show the blackest points. Pick the "color sampler tool" to one of the dark pixels (to keep an eye on color balance anytime)
3. Add an adjustment layer - Arcsin curve
4. Add another adjustment layer - Arcin curve, if needed
5. Add adjustment layer - Levels, adjust all colors to be the same in the blacks
6. Flatten a copy, name it "stars"
7. Flatten a copy, name it "starless" and run StarXterminator
8. On the starless version, apply substract as layer mode and create a copy named  "stars only"
9. Apply as Linear Dodge to the "stars only"
10. Remove hue of "stars only" + adjust curves as needed

Second file:

1. Create a new document
2. Copy paste each of the RGB channels as layers (of the starless version)
3. Ha layer above all layers, OII layer below, SIII as last layer
4. Hide all, except SII layer, copy, create a mask on OII layer, paste in the mask, invert the mask
5. Hide all, except OII layer, copy, create a mask on OII layer, paste in the mask, invert the mask
6. For each of SHO layer -  Add an adjustment layer - Hue/Saturation. Apply as coloration layer. Apply to edit the layer below only. Boost saturation to 100.
7. Pick a color for each Hue layer
8. Make a copy of this for backups of HSO layers masks, before curve editing
9. Edit the curve of each mask on the HSO layers to make it more natural
10. Add adjustment layer - Levels, if needed to flatten colors again
11. Add adjustment layer - Selective color > green channel: remove all cyan
12. Add more adjustment layers for selective colors, adjusted per color taste
13. Contrast adjustments
14. Would add noise correction plugin here, for real shooting

Back to first file:

• Once done color adjusting and doing all edits on the nebula, flatten + copy back to the first document, below the "stars only" layer

So...

• What would you recommend for this picture to look more interesting?
• What would you change in the editing process?
• What do you pick for blackest pixels? Do you bring it as close to 0 as possible, or do you leave room to be greyer?
• Colors, colors... I know it's very personal to each but... how do you decide to stop with X color and not another? When to know to stop in the saturation? Do you use references? Do you just walk away and come back minutes... hours... days later to it? I feel like after being on the screen for too long, I get lost.
• How do you adjust your contrast to make it pop more, without killing your data?

Thank you for taking the time to read this... if you made it until here

Cheers and clear skies to you!


https://www.astrobin.com/full/1h0oba/0/