The seahorse in Cepheus

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Carles
Posts: 193
Joined: Thu Jul 30, 2020 5:06 pm

Re: The seahorse in Cepheus

Post by Carles »

Nice looking Sea Horse, Stefan!! :D

Perhaps I would have used "Cap green" on Colour module for some gradient, and stronger/higher values on final denoise
but looks very good, :) nice dark nebulosity right there :D

Regards
Carles
Stefan B
Posts: 431
Joined: Sat Oct 31, 2020 8:59 pm

Re: The seahorse in Cepheus

Post by Stefan B »

Thanks, Carles!

Actually I used Cap green with 100% as a last step in the color module (I always do that though it's not recommended as a default step). Didn't make a difference since in MaxRGB green pixels appeared to be randomly distributed. Maybe I should have increased the value for Reduce green bias slider :think:

I guess ST suggested the correct strength for Denoise but I don't like the completely denoised look, so usually I bump up the Equalize noise grain slider to 33%. Probably a matter of taste. My recent Cave nebula image is an exception for me since there I liked the completely denoised look and left it as it was without equalizing noise grain.

Regards
Stefan

PS. FYI, from the documentation on noise grain equalization:
The 'Grain Equalization' parameter lets the user reintroduce removed noise grain in a modified, uniform way, that is; appearing of equal magnitude across the image (rather than being highly dependent per-pixel signal strength, stretches and local enhancements as seen in the input image).

The 'Grain Equalization' feature an acknowledgement of the "two schools" of noise reduction prevalent in astrophotography; there are those who like smooth images with little to no noise grain visible, and there are those who find a tightly controlled, uniform measure of noise grain desirable for the purpose of creating visual interest and general aesthetics (much like noise grain is added for a "filmic" look in CGI). The noise signature of the deliberately left-in noise, is precisely shaped to be aesthetically pleasing for precisely this purpose.

Lastly, it should be noted that the 'Grain Equalization' feature only shapes and re-introduces noise in the luminance portion of the signal, but not in the chrominance (color) portion of the signal.
Carles
Posts: 193
Joined: Thu Jul 30, 2020 5:06 pm

Re: The seahorse in Cepheus

Post by Carles »

Right, I downloaded the JPG and indeed, CAP green at 100% did very little, but some Reduce Green bias did the trick specially on the green-ish gradient in the center .

About the denoise, on first step on Track off, I raise it quite a bit, as it has attention to detail thanks to Track, later on, play with last layer paramenter and also Scale Correlation and some Brightness detail Loss

First Step Grain size, should be raised to the point all looks smoth, it won't be as blurry as it shows on that step, as Track will be aware of detail.

but as always with this... more integration the better haha the less hard you have to work on all this :)

Regards

Carles
Stefan B
Posts: 431
Joined: Sat Oct 31, 2020 8:59 pm

Re: The seahorse in Cepheus

Post by Stefan B »

Carles wrote: Fri Sep 01, 2023 8:04 am ight, I downloaded the JPG and indeed, CAP green at 100% did very little, but some Reduce Green bias did the trick specially on the green-ish gradient in the center .
Could you post how it looks afterwards? Have to admit on my screen it already looks okay. MaxRGB didn't have green dominant patches if I remember correctly :think:
Carles wrote: Fri Sep 01, 2023 8:04 am First Step Grain size, should be raised to the point all looks smoth, it won't be as blurry as it shows on that step, as Track will be aware of detail.
Yeah, aware of that. It has all been smooth. But equalization step reintroduced the noise.
Carles wrote: Fri Sep 01, 2023 8:04 am About the denoise, on first step on Track off, I raise it quite a bit, as it has attention to detail thanks to Track, later on, play with last layer paramenter and also Scale Correlation and some Brightness detail Loss
In my experience raising the initial pixel value heavily beyond ST's suggestion results in low SNR regions to be blurred too much for my taste ;) And with regard to the other parameters I don't even know what they are doing... :shock: Have too look in the documentation. What are your experiences with them?

Regards
Stefan
Carles
Posts: 193
Joined: Thu Jul 30, 2020 5:06 pm

Re: The seahorse in Cepheus

Post by Carles »

Hi Stefan,

sure, here you have Max RGB of Screenshot of your image (simply downloading jpg, ST don't let me open..so screenshot it is)
maxRGB.jpg
maxRGB.jpg (424.06 KiB) Viewed 53734 times
now, Max RGB after reducing some Green
MaxRGB after.jpg
MaxRGB after.jpg (396.39 KiB) Viewed 53734 times

And the end result
result after Red.Green.jpg
result after Red.Green.jpg (595.32 KiB) Viewed 53734 times
and yeah, is worth checking documentation for Denoise, there are things to consider :)
you have it on page 277 (at least on the spanish translation i did for 1,8 , but will be around there, if not, on ST "? " icon on each parameter it tells what it does :)

Carles
Carles
Posts: 193
Joined: Thu Jul 30, 2020 5:06 pm

Re: The seahorse in Cepheus

Post by Carles »

---- and BEFORE adjusting Green bias

(sorry, didn't let me uplpoad on previous message...dunno why )

Compare and let me know :)
Attachments
result before Red.Green.jpg
result before Red.Green.jpg (579.62 KiB) Viewed 53734 times
Mike in Rancho
Posts: 1158
Joined: Sun Jun 20, 2021 10:05 pm
Location: Alta Loma, CA

Re: The seahorse in Cepheus

Post by Mike in Rancho »

Three pics max within a single ST forums post. :D

Green cap is kind of a matter of "it depends." I think this is especially true with dust, as in this target. Green (as a component with the R and B of course) can add richness and some needed yellow into those dusty areas. In fact, since reducing green raises magenta, one has to be careful about inducing too much pink or purple. :shock:

I do see a little bit of that in the last post Carles, and Stefan's original seems to me to have the appropriate amount of green/yellow richness for globs of darkish dust. I'll often leave things alone, at least if I don't see obvious improper green tint to stars or whatnot.

Of course a lot probably depends on the individual eye, and the monitor. I still haven't used my hardware calibrator on the new monitor here, so that could be part of it. Maybe I'll do that this weekend.

Note too that on a finished image, if reopened non-linear non-tracking, MaxRGB may be a bit different from what is was in the Color module during tracking. So you'd have to decide case by case whether it needs (possibly another) green cap. Unsure of the reason, perhaps it results from denoise - which you can sometimes see alter the overall image hue slightly - or even SS if that was run.

Pixels of grain and scale are also a matter of taste I would think. What ST chooses for the initial grain size I believe is primarily rolled over from settings in prior modules (kind of like DAF/IFD in the very beginning). So I would consider it an educated guess that's hardcoded into the program (not AI, I think ;) ), and it still needs to be reality checked by eye to see if it is appropriate.
Carles
Posts: 193
Joined: Thu Jul 30, 2020 5:06 pm

Re: The seahorse in Cepheus

Post by Carles »

of course that was just a way to il.lustrate the difference. Reduction of green was perhaps too much, in a magnitude of 1.05 might be OK.
the original has a green-ish yellow. but then again, depends on monitor and taste. For me was too green-yellow.

but all depends on how one wants to represent it.
Stefan B
Posts: 431
Joined: Sat Oct 31, 2020 8:59 pm

Re: The seahorse in Cepheus

Post by Stefan B »

Thanks, Carles. I had a look at it now in different monitors and know what you mean. 1.10 is a bit too much for my taste and I am still fine with my rendition but your are right that 1.05 would probably be fine, too! :thumbsup:

What surprises me is the MaxRGB screenshot. It definitely didn't look that way when I viewed it with tracking on. When using Cap green with 100% shouldn't there be no green dominant pixels in the final image?

Regards
Stefan
Carles
Posts: 193
Joined: Thu Jul 30, 2020 5:06 pm

Re: The seahorse in Cepheus

Post by Carles »

Hi Stefan,

yes,...I don't know, perhaps is because it was an screenshot of a JPG? haha not no idea how it's rendered and why there is green remaining.

I think Cap Green does not eliminate all green, but rather targets the gradient greens, so it could still be some green left contributing to the yellow. But at least on my Laptop's monitor and Phone screen, both seemed a bit green-ish. Not major, but specially when you compare to the perhaps a bit extremist 1.10 green reduction, is more noticiable. Agree that around 1.05 or so can be OK. Coloring is hard, but when there's too much yellow background or the starfied seems too yellow, tend to try to level it out somehow. So even though 1.10 was perhaps "too much" for the nebulosity on the horse head, the star field colour, to me is more balanced. it is a personal taste after all, I guess.

Regards,

Carles.
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