Typical PixInsight tools for Hubble Palette processing

[topboxman]

This is my second post related to processing NB images with PixInsight because I really didn't get the answer I wanted in other post. First post: http://pixinsight.com/forum/index.php?topic=4731.0

The only tool I use to remove green color due to Ha dominating in the green channel is "SCNR". The problem with SCNR is that it removes ALL of green but it gave me decent results but is this the correct procedure? It sounds too simple.

I have seen many tutorials using Photoshop but I don't have Photoshop. This is a sample tutorial using Photoshop:

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

It uses Photoshop's Selective Color tool to create Hubble Palette image. PixInsight does not seem to have this tool or similar.

What PixInsight tools can I use besides SCNR that can create a nice Hubble Palette and what are the procedures? I have Googled for Hubble Palette processing with PixInsight and found one but it uses "SCNR". I have seen people modifying the linear image by stretching before combining but can you run Background Neutralization and Color Calibration on non-linear images?

I know my question is too generic and there may be different methods depending on the objects.

If you would like to have some fun processing my images, I uploaded a zip file of Bubble Nebula containing the following:

Calibrated and stack of:

21 x 15 minutes of Ha: Good seeing condition
31 x 15 minutes of Oiii: Below average seeing condition
12 x 30 minutes of Sii: Average seeing condition
8 x 10 minutes of Red: Ok seeing condition
8 x 10 minutes of Green: Ok seeing condition
8 x 10 minutes of Blue: Ok seeing condition

The zip file is 115 MBytes.

http://www.sendspace.com/file/y2aji9

Click only on "Click here to start download from sendspace" link at bottom of web page. Do NOT click on any "DOWNLOAD" or "Play Now" buttons.

Thanks,
Peter

[Philip de Louraille]

Hi Peter, did you read this thread?
http://pixinsight.com/forum/index.php?topic=2513.msg25601;topicseen#msg25601

[topboxman]

Hi Philip,

Yes I have seen this thread but I am not sure how it helps me. It does not say much except to try out different pixel math forumula which I have. What I am trying to do is after color combination for Bubble Nebula I recently captured:

Red = SII
Green = Ha
Blue = OIII

It resulted at least 95% green color due to huge Ha dominance over OIII and SII. Then what?

Thanks,
Peter

[Carlos Milovic]

Histogram and Curves...

[Philip de Louraille]

The trick on NB is to treat each channel independently. So like Carlos states, get the most details you can on each by whatever tools PI offers. Then you assemble them in color.
If the color image is too green, then reduce that intensity at the end or play with merging the bands a little.

There are really no good rules. If your end goal is a pleasing image, then work to that end. NB is not what the human eye sees naturally so there aren't any rules about what needs to be done to get to that goal.

[topboxman]

Thanks for the responses. Mainly I was asking how to have more control of the colors instead of just using SCNR. I'll try treating each NB channel independently before color combining. I have never made each image non-linear before color combining.

Peter

[Ioannis Ioannou]

Peter,

take a look:

http://pixinsight.com/forum/index.php?topic=2346.0

http://pixinsight.com/forum/index.php?topic=2351.0

[topboxman]

I have seen them. Unfortunately Niall Saunders tips are missing screen shots which makes it a little difficult to follow. A picture contains a thousand words. Maybe my ISP blocked the links to the screen shots. Can you see the screen shots?

Peter

[Ioannis Ioannou]

Yap, you are right, the screenshots are not there anymore - I just copied/pasted the links from my browser's bookmarks.
Also the link with the XPM is not available anymore 
Pity. Juan, is there something to do with this ? It was a very helpful thread 

Anyway, the main idea is there in the wording. You have to play with curves, with H (hue) to re-map the colors to your like, the way more or less is happening with selective color is PS. It takes 3-4 (or more) tries until you figure it out, but it works.