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Author Topic: M33 Gradient problem  (Read 2587 times)

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Offline Eccoskies

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M33 Gradient problem
« on: 20:13:05, 10 October, 2012 »
Hi Guys,

I'm really struggling with gradients in my image of M33 i took a while ago. I've seen a few tutorials on removing it using layers etc in PS but i'm struggling to get to grips with it  :embarrass:
Would anyone like a play with the image to see if you can get rid of the gradient and let me know what you did  :pray:

cheers
Mark
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Mark
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Offline blinky

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Re: M33 Gradient problem
« Reply #1 on: 20:35:44, 10 October, 2012 »
How is this?
Duplicate image, apply massive gaussian blur, so the image is only showing the gradient. Go back to the original, select Image, Apply Image. In the popup, drop the image selection box and select the copy of the image (The one you just blurred), in Blending set it to Subtract, set the offset to 50 click OK. Finally adjust the levels back down to what they should be.

Offline chris.bailey

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Re: M33 Gradient problem
« Reply #2 on: 20:35:51, 10 October, 2012 »
Mark

Howzat. PixInsight DBE (Dynamic Background Extraction). 6 Mouse clicks.
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Offline Eccoskies

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Re: M33 Gradient problem
« Reply #3 on: 20:57:47, 10 October, 2012 »
Cheers guys  8)

Blinky - i had tried this method before and didn't get the right result i wanted however, i played with the offset and seemed to get it much better this time using a value of 50 :thumbup:

Chris - PixInsight seems like a powerful piece of kit but being a true Yorkshireman i don't like spending money  :yakillinme: thanks for the result though  :urock:

Mark
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Mark
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Offline blinky

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Re: M33 Gradient problem
« Reply #4 on: 21:07:37, 10 October, 2012 »
Pixinsight is good Mark, I now use it for all my processing but I saw that you were using it so I went back and processed it in PS for you. 

Offline stealthtech

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Re: M33 Gradient problem
« Reply #5 on: 21:08:41, 10 October, 2012 »
Hi Mark

I've had a play with this, but don't have PixInsight, only PS, so this is what I did ( much like the steps here).

As in the pics below, in PS duplicate the image and call it 'copy'. Go to Filters > Dust and Scratches and set the pixel radius to approx 40. Select 'Healing brush' and Alt click a part of the image round the outside of the smudged galaxy (not the galaxy itself but the grey background). Apply this to the image to smooth out the smudged galaxy part (little and often), and just leave the smudged image with the gradient background. Click on the original image first, then go to Image > Apply Image and, here's the important bit.....set the 'Source' as the copy image and the 'Target' as the original (the 'Target' is applied when you clicked back to the original image). Select 'Subtract' on the drop down list and then set the 'Offset' button to 10% (this lightens the image so play around to see what suits your requirements). I think that's pretty much what I did.

Not saying this is the definitive way, but it's a pretty quick way to clean it up. A bit like creating a digital flat, really  ;). Don't like posting the finished pic, only the steps.....that bit's up to you, fella  :harhar:!!!

Good luck mate,

Martyn

.....nice image, btw  :thumbup:!!!



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Offline Eccoskies

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Re: M33 Gradient problem
« Reply #6 on: 21:28:52, 10 October, 2012 »
Martyn,

Cheers matey  :urock: that'll give me something to play with  :yes: i'll post the fina, pic up once i've sorted it  :thumbup:

Mark
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Offline Carole

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Re: M33 Gradient problem
« Reply #7 on: 21:33:30, 10 October, 2012 »
I did a gradient Mask in photoshop:

Duplicate layer
Make a mask in the new layer
click on gradient tool and the gradient icon which shows a left to right gradient.
Activate the layer rather than the mask, and draw a line on the image in the direction of a gradient, this will make the mask create a gradient to match (though depending on how you draw the line you might need to invert the gradient (Image image/adjust/invert).  Then use levels to adjust the background until you are happy with the result.

Flatten layers & voila!!  


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Offline roundycat

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Re: M33 Gradient problem
« Reply #8 on: 21:52:14, 10 October, 2012 »
quick mask in PS on the background, no layers or masks.

Dennis

Offline PaulB

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Re: M33 Gradient problem
« Reply #9 on: 06:46:09, 11 October, 2012 »
Hi Mark,

I ran your Messier 33 image through GradeX, then a Space Noise reduction (Noels Tools) in CS2 and a little curve adjust and blur then Un-Sharpmask.
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Offline Eccoskies

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Re: M33 Gradient problem
« Reply #10 on: 18:05:52, 21 October, 2012 »
Cheers for all the efforts guys  :thumbup: I'll give each option a go and see which suits me best  :urock:

Mark
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Mark
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