[RCC] SHO or SHO-Foraxx for NGC 7000 ? Requests for constructive critique · patrice_so · ... · 8 · 555 · 1

Dear all, 

Trying to delay the investment in a mono setup (yeah it's better, but its expensive), I now use two dual narrowband filters to be able to compose SHO images using a OSC camera (asi294MC pro). So far so good, I had some fairly good result, one being even nominated top-pic. 

I now have collected about 22 hours of data on NGC 7000. After processing it several time, I have difficulties to make a decision between a classical SHO version and a SHO version created using the Foraxx palette. In fact, I have the feeling that the Foraxx trades better colors (more reds) against less details (on the wall for instance). I tried to improve the Foraxx as much as I could, but still think that the classical SHO is superior because it is much cleaner. 

At this point, I would gladely recieve guidance on 
- What is regarded as the better image
- How to improve any of these two image. 

SHO : https://www.astrobin.com/ofvm7w/D/#rC
SHO-Foraxx : https://www.astrobin.com/ofvm7w/D/#rD

The entire processing was done in Pixinsight. I stacked both DNB images and the RGB image (for stars) in WPBB, registered the frame, cropped, extracted the Ha, Sii and Oiii (combining both DNB Oiii stacks). I applied blurX and removed the stars. I applied linearfit before combining the layers either with Channel combination or the Foraxx script. Then it is stretched improved with curves (using sometimes colors masks), local contrasts, etc, before a final noiseX pass and the addition of the stars. 

Let me close by clarifying that I agree that one needs to be able to decide what ones like the most. However, after 3 years in the hobby, I feel now that I need also to developp some new abilities and tool to be able to get where I want. I sometimes have difficulties to identify what it is I really like or dislike in an image and here, the community can provide crucial inputs. 

Many thanks & clear skies, 

Patrice

I prefer the color contrasts in the Foraxx version, but the saturation (actually, less saturation) of the SHO version. That's just me, though, and you should trust your own decision on which is better. Any time I struggle to decide which version I like better, or whether I really like the hues and saturation I have chosen, I find that if I step away from the image for a day or two and then come back, my opinion crystalizes nicely. I'll either decide, "Boy, I really hate that since it looks overcooked" or, "Wow, that is really, really nice." It doesn't mean I am a better judge after a day or two, but I am definitely more clear in my own mind if I step away.

- Jared

The two look pretty similar to me, with the Foraxx version being a bit more contrasty. In all honesty, I think that you could bring out more saturation and a bit more contrast in your "classic" SHO version, just with a bit of curves work. 

I think CurvesTransformation is often overlooked, and curves are one of the most powerful tools in the PI processor's toolbox. I suspect you could preserve the improved wall details of your classic version, while also gaining some increased saturation and contrast, with some additional curves work. 

One of the best tools for dialing in the exact colors you want are the a and b curves in CurvesTransformation. These use a Lab space transformation to allow you to shift colors in a way that the hue curve cannot. You then also have the chroma and saturation curves, which can do a pretty good job brining out the colors and color contrasts. So you don't necessarily need to lose anything (the Foraxx version does look a little softer) to gain the more contrasty, saturated look of the Foraxx version.

patrice_so:
Dear @Christian Großmann,  @Jared Willson, @Vinny Vent, @Jon Rista

Many thanks for your kind and valuable comments. I share completely the view that one needs to be able to make decision about his own preferences. In my case, the wow effect occured with the Foraxx. However, I do recognize some  qualities in the SHO that I have difficulties to reproduce in the Foraxx version. I will keep trying to get a cleaner version of the Foraxx, keeping the hand careful on the saturation. I am a bit frustrated at this point and I suspect that the very type of color combination makes the issue a bit more tricky that a classical case of saturation fallacy. 

I will get back when I have something. 

Clear skies, 

Patrice

Have you tried the NB color mapper? You can literally customized the color of each channel individual and watch it update live in the preview. You may find it easier in the future. 

Script is here: https://pixinsight.com/forum/index.php?threads/new-script-nbcolourmapper.21673/


Tutorial is here: https://www.youtube.com/watch?v=0XxB-sOFD0Q

Dear all 

Many thanks for your valuable comments. That helped a lot. Combining them, I got the following outcome, which is the first I am happy with because it does no longer look like a bi-colour image where on has tried to get some third colour playing with curves. I benefited from your advices and from a post by Brian Puhl on FB. 

https://www.astrobin.com/ofvm7w/F/



Of course, learning never stops. Any further comment, criticism or advice is most welcome. But I wanted to thank you. 

Clear skies, 

Patrice