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Derbyshire Dave

Help please, Narrowband Colour Balance

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Derbyshire Dave

I posted an image of the Soul Nebula yesterday.. Only 20 minutes of data, so room for lots more data..

 

Soul3 18 mins RGB combined V3A

 

Whilst I'm pleased with the detail, I think the image is way too green ..

 

Process,

    1)Stacked in DSS with 28 darks, which removed the amp glow (phew!).

    2)Processed in Photoshop CC, with some use of Gradient Xterminator and Neil Carboni's actions(Noise Reduction/Stars Smaller).

    3)Converted to Hubble Palette using method pointed out here..

 

http://bf-astro.com/hubblep.htm

 

      4)Many further tweaks,

 

I THINK ITS JUST TOO GREEN!!

 

      I guess this could be:

    a)The way that I combine the RGB. Ha is much stronger, but unsure how to really 'tone it down'.

 

    At the link above, it says..

    'This image is created by first stretching the SII, Ha and OIII images so their levels from dark to bright are similar... as shown in the above histograms in Fig 1.'

       

I can't find a way of doing that, my histograms are just very narrow. This is my Un-stretched Ha file..

Ha HistogramJPG

 

    b)I've done something wrong in the Hubble adjustment. I think this is OK though, and I've created an action for the Selective Colour sequence.

 

I've uploaded my Sii,Ha and Oiii file to Flickr.. I uploaded them as TIFF, but think the downloads are jpg, which might not be enough detail.

Files To Process

 

I can e-mail the original TIFF's to anyone who has the time to have a look.

 

Any help to address the colour balance would be an enormous help.

 

THANK YOU

 

 

Thank you

Dave

 

 

 

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Graham

Open the image in ps.

go to selective colour.

choose green

alter to suit.

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Derbyshire Dave

Thanks for coming back so quick Graham. I tried that, but could't seem to get anything to do the job. Would you have a minute to try it on my image and let me know the slider positions if you can tone it down.

 

Thank you Graham

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Ron Clarke

Dave, try HLVG from Deep Sky Colours I think?

(Hasta La Vista Green)

Edited by Ron Clarke
added text

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Derbyshire Dave
3 hours ago, Ron Clarke said:

Dave, try HLVG from Deep Sky Colours I think?

(Hasta La Vista Green)

That's a great help Ron, thank you. I'll give it a try

Dave

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red dwalf

HLVG as ron says is very good at getting rid of green, although there are other ways, maybe the simplest would be to view the histogram in photoshop, the green channel should show up as the most dominant colour and further to the right than the red and blue channels, usually blue is very weak, bottom right box in photoshop should be a tab called channels, select the green channel only and either levels or curves to reduce the green, you can do the same selecting levels when all channels are selected and instead of rgb select the green channel only and reduce it, may ways to skin a cat in photoshop.

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Derbyshire Dave

Ron,

 Thank you. I tried HLVG, it certainly makes a big difference.

Rob, Thanks, and nice to hear from you! I do struggle with this because my histograms are so narrow. I somehow think I should have done this early on in the process, rather than trying to catch up later.

 Will give it some more goes..

 

Thanks both

 

 

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Graham

Hi David.

Hope you don't mind but I copied your image on here and had a quick play with it.

Unfortunately being a JPEG there is not a lot of room to maneuver with it.

 

Click on it a couple of time for full res.

 

spacer.png 

Edited by Graham

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Derbyshire Dave

Graham,

 Thank you, the colours are a great improvement.

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