Request for critique

21 replies808 views
Rabeea Alkuwari avatar
Hello,

Id like to request for critique for one of my favourite images I ever took..I saw some flaws while processing and was wondering if it was visible to a third eye 👁️ 


You can find the full resolution version as a revision 

https://www.astrobin.com/z3js8a/0/
andrea tasselli avatar
Nicely done but not the palette I would ever choose.

P.S.: and black point way too much in the red.
Tony Gondola avatar
Over all I find the image to be a bit over-baked, too much contrast and color saturation overall. I also feel that the stars are pulled down too far. When viewing the image normally, not pixel peeping, the stars are almost not there.
Rabeea Alkuwari avatar
Thanks @Tony Gondola @andrea tasselli - noted on the stars, usually for nebuale with faint details and less interesting galaxy field i prefer reducing stars to highlight whats more interesting to me which is the faint neboulosity 

What im looking for is feed back on processing flaws, not necessarily color or saturation. hint: this is a mosaic 
however sometimes i wonder since I have a form of color blindess (Deutan: less sensitive to green/red) how people with normal vision see the picture
Tony Gondola avatar
I would consider color balance and saturation to be a part of image processing. I don't don't know how a certain degree of color blindness would effect things but I'm certain it would. Even using a un-calibrated monitor can have a big effect. I would think that having a number of people look at the image (as you are doing) is a great idea.
Daniel Cimbora avatar
I agree with Andrea – wonderful image, but the red-tinted background detracts.  I think the nebula would pop with a more neutral background.
Well Written
John Hudson avatar
I like it a lot!
Oscar avatar
so, looking at it closely, I see:

1. background does have some red tint; Colormask script is good for manipulating just a certain color without changing the tint on the whole image
2. stars are just right - it's good to make it feel like they're just in the background, and not "in our face"; pushing them more would be a bad decision
3. the color of the HA is somehow not pleasing - I guess I like less green in the HA maybe? green looks better in the highlights of the HA, more than in the rest of the histogram. (you can get that fiery look if you adjust green just right)
4. OIII looks okay, could've possibly made it pop more though

I think it's a decent image overall
David Zimák avatar
I like an image overall.. of course there are few things I would do differently at my taste

a/ stars little too far reduced .. 15-20% more stretch will be nice

b/Red could be bit deeper.. less orange tint

c/OIII - I prefer more green tint on that emission you will see if you look through that filter by your own eyes. I know many shows it as almost blue but definitelly it is not .. at least in the reality.

But still, It is very nice and wide field , decent amount of details in nebulae, not oversharped with AI tools and so you have got like 👍 from me.

David
Georg N. Nyman avatar
Overall a very nice and well done image - here my few points for consideration:

1. Black point is too red - this is unreal and harms the overall impression
2. Stars are too much reduced, probably slightly more visible would be beneficial
3. The red in the image is for my liking a bit to "brownish"

Positive is - the image is not oversharpened, not oversaturated and nicely composed

CS
Georg
Helpful Concise
Rabeea Alkuwari avatar
thanks @Georg N. Nyman @David Zimák ​@Oscar @John Hudson @Daniel Cimbora 


Valid points gents around the black points and color of Hydrogen. however the reason I opened this thread is to see weather the stitching point of the mosaic is clear to anyone and it seems like it doesnt. (there seems to be a line of different saturation to me? or a color shift between the two panels)

i've uploaded a newer version here https://www.astrobin.com/x8h86b/
andrea tasselli avatar
I think the revision got it worse (or I mis-remember). The stitching between the two panels I still can't see. But I see mismatching (abrupt change between one emission area with the next badly stitched together) between Ha and OIII and an increase in noise in areas. On top of that saturation is gone even higher and the black point is even redder and stars even fainter (see caveat mentioned before). It's your jig so you can play like you want but this is what I found unpleasing. And the hues, that hasn't changed either. 

Nice PN you got there, by the way…
Georg N. Nyman avatar
I agree to almost all what Andrea had written before…. worse than the original, well maybe regarding the saturation, which is far to high and worse regarding the black point in those areas where there is (almost) no HII emission. Are you working with a calibrated monitor? 
Try to reduce the saturation by at least 20% and set the HII-free areas with a mask to almost colorfree (without harming the stars). 
That would be my approach - but please, keep in mind, this is a question of preference of course!

CS
Georg
Rabeea Alkuwari avatar
Thanks everyone for the look, Correct @Georg N. Nyman I think its a question of preference at this point. The dark areas are quite equal in RGB values now from where i was inspecting (Non Ha areas).
Georg N. Nyman avatar
just to show you, what I ment - that is my version of that famous target - as I suggested, for me, my preference was to go lighter regarding saturation and to make sure that the background is not that red. And yes - that ment to sacrifice HII emission in the background.
CS
Georg



andrea tasselli avatar
PN name: Pa-28 (Pk076.8-08.1)
Rabeea Alkuwari avatar
andrea tasselli:
PN name: Pa-28 (Pk076.8-08.1)

Quite impressed with the redcat honestly - nice detail for a short-ish Oiii integration. Saturation made it pop too 😂
andrea tasselli avatar
I'd be more impressed (and deeply envious!) with the quality of your skies.
Well Written Respectful
Rabeea Alkuwari avatar
andrea tasselli:
I'd be more impressed (and deeply envious!) with the quality of your skies.

The middle east has less cloudy nights than anywhere in the world (i think) - however seeing conditions here are bad to average all year round with desert dust. In qatar the best sky in the country is bortle 4.5. So nothing really to be envious about 😅
andrea tasselli avatar
From where I stand B4.5 sounds like AP nirvana…
Brian Puhl avatar
I kinda glanced over some of the previous replies.   From a distance the image looks neat.   

When you get up close it's another story.  

This image just screams color masking to me.   I'm not positive if that's what you did, but there is little to zero blending between the Ha/Oiii data here.   It's one, or the other.  The colors just don't blend, at all.    I really think you tried wayyy too hard here, when a simple Auto-STF + HOO combination would have produced a superior image.    Less is more.   Don't buy into all the fancy tools.   I think potentially you could have a very good image, but you need to go back to the drawing board and rethink this process.
Rabeea Alkuwari avatar
Brian Puhl:
I kinda glanced over some of the previous replies.   From a distance the image looks neat.   

When you get up close it's another story.  

This image just screams color masking to me.   I'm not positive if that's what you did, but there is little to zero blending between the Ha/Oiii data here.   It's one, or the other.  The colors just don't blend, at all.    I really think you tried wayyy too hard here, when a simple Auto-STF + HOO combination would have produced a superior image.    Less is more.   Don't buy into all the fancy tools.   I think potentially you could have a very good image, but you need to go back to the drawing board and rethink this process.

Hi Brain, the only color masking that was conducted was through selective color on PS. Its been a trusty companion for the most part. I think i felt what u were referencing with this nebula and my opinion was (after reviewing similar HOO renditions) is that that is a probelm that comes with HOO (comparing to SHO). If you have the time can you share which areas u felt the blending of two channels were not smooth? I suspect its because u we were zooming in too much on a jpeg photo? Could be wrong tho