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Will this crazy processing idea work on my background mottling?

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#51 miwitte

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Posted 07 January 2018 - 06:30 PM

Here is the typical mottle after TGV, MMT, multiple DBE and LF. If I go too hard on TGV and MMT its only worse.


mottled mess.JPG

#52 NorthField

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Posted 07 January 2018 - 06:37 PM

You guys know better than me, but shouldn’t dbe be done prior to any nr, or anything else, except decon?

#53 pbkoden

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Posted 07 January 2018 - 06:46 PM

miwitte, your pixelmath is exactly correct. Also, it looks like your mottling is a smaller scale than what this process is intended to get rid of. You should be able to get most of that out in the noise reduction. Have you worked the noise reduction per Jon Rista's website? https://jonrista.com...duction-part-1/

 

I like to do it after noise reduction, right before any stretching. Until you do the noise reduction, you really don't have a good handle on what your background looks like.



#54 schmeah

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Posted 07 January 2018 - 07:27 PM

The mottling is fairly easy to correct in a single step in PS, applying a flat background in lighten blend. As was previously discussed it is simply filling in the valleys, adding a pedestal. There must be a comparable step in PI?

 

Derek

 

mottlingedit.jpg



#55 pbkoden

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Posted 07 January 2018 - 08:01 PM

The mottling is fairly easy to correct in a single step in PS, applying a flat background in lighten blend. As was previously discussed it is simply filling in the valleys, adding a pedestal. There must be a comparable step in PI?

 

Derek

 

Pixinsight is less an image editor and more a math toolkit for images. This is one of those things that's not nearly as easy to do in PixInsight as it is in PS, but it's possible with some tricks.



#56 mikefulb

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Posted 07 January 2018 - 08:22 PM

The mottling is fairly easy to correct in a single step in PS, applying a flat background in lighten blend. As was previously discussed it is simply filling in the valleys, adding a pedestal. There must be a comparable step in PI?

 

Derek

 

If I understand correctly the technique discussed here is adding noise instead of a flat background to make it blend in better.  You could do the same thing in PS using your suggestion but first use the 'Add Noise' filter to season the flat background properly.

 

I've done that sometimes after minimizing stars in PS to avoid the flat looking halos left behind the stars when I'm sloppy about masks.



#57 miwitte

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Posted 07 January 2018 - 08:25 PM

So I just got PS a couple weeks ago to see if I could get a grip on my dbe issue with gradient xterminator which has actually given me pretty good results. Now after reading this maybe I need to try the PS method to smooth things out. I am finding some really cool things you can do with layers that simply aren't there( or not as easy) in PI. Im learning about layers and blending just not sure completely how to create a grey background and a pedestal in PS. I'll have to read your post again and try it and see what happens. Sometimes reading steps and duplicating seems easy enough for someone with a ton of PS experience but for someone with 2 weeks not so much. I have almost a year with PI and PS has a pretty large learning curve as well. Thank god for video tutorials or I would really be lost.

 

processing is is not a easy task and its very easy to get spun around and not know which end is up....


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#58 schmeah

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Posted 07 January 2018 - 08:46 PM

The mottling is fairly easy to correct in a single step in PS, applying a flat background in lighten blend. As was previously discussed it is simply filling in the valleys, adding a pedestal. There must be a comparable step in PI?
 
Derek

If I understand correctly the technique discussed here is adding noise instead of a flat background to make it blend in better.  You could do the same thing in PS using your suggestion but first use the 'Add Noise' filter to season the flat background properly.
 
I've done that sometimes after minimizing stars in PS to avoid the flat looking halos left behind the stars when I'm sloppy about masks.


Exactly. The mottles or "valleys" are darker and smoother. So bring the level of the background up to blend properly and add some uniform noise to taste. So it's actually two steps when done properly.

#59 miwitte

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Posted 07 January 2018 - 09:28 PM

Fantastic!

On the right is before, on left is after. So do you keep increasing the multiplier to get rid of salt or pepper? My thought is also that the value of the random noise being used in the image would effect either salt or pepper.

Definitely something I need to explore. I also need to re-evaluate using cosmetic correction so my salt and pepper isn't as bad.

At this point would you do more TGV and MMT? I use Jons tutorials, but I found if I got them too smooth when linear, later in in non linear they would exhibit motteling and the advise was so allow for some salt and pepper in the image to reduce that effect later on. This is a very cool trick that a lot of us newbs could really benefit from.
Thank you so much for this its awesome! Now if anyone has a similar few screen shots to reduce this in CC that would be extremely helpful as well.

mottlefix.JPG


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