Pelican and North American bi colour mosaic

[steviemac500]

I've added another 40 hours of O3 to the 60 hr HA mosaic. The colours have not come out as I expected and I am having issues with what i think is a gradient in the O3 data, leaving a blueish cast to the background of the image. I don't know whether to up the O3 data to match the HA and start again or retake the O3 entirely. Any help would be appreciated.

Hi res link - http://astrob.in/304503/0/

Update - please see revision below at bottom of post with new link to hi-res. Thanks Sara!!!

http://astrob.in/304511/0/

 

[swag72]

Wow - That is some going!!!

Out of interest, have you added a luminance layer? 

[steviemac500]

No i haven't Sara. Would that be using the HA s the lum?

[swag72]

Well I would consider two things and I think that this would help your gradient problem significantly.....

1) Use your Ha as a luminance layer. While you have it as a layer and before you flatten it, use the colour select tool or colour balance (so you can lower the blue in the shadows if you want).

2) Convert your Ha OIII image to greyscale and use that as a false luminance..... see which works better.

I always put some luminance of another on my images..... you can really play with the colours them, not worry how it all looks than slap a luminance on the top and hey presto..... all the detail with all the colour  

[steppenwolf]

I have often found that a false luminance channel as Sara's option number 2 works very well in a bi-colour scenario as it gives you a tremendous amount of control over the image, allowing quite wild colour manipulation controlled by the 'luminance' to remove unwanted colour artefacts.

[steviemac500]

29 minutes ago, swag72 said:

Well I would consider two things and I think that this would help your gradient problem significantly.....

1) Use your Ha as a luminance layer. While you have it as a layer and before you flatten it, use the colour select tool or colour balance (so you can lower the blue in the shadows if you want).

2) Convert your Ha OIII image to greyscale and use that as a false luminance..... see which works better.

I always put some luminance of another on my images..... you can really play with the colours them, not worry how it all looks than slap a luminance on the top and hey presto..... all the detail with all the colour  

I went for option 1. What a difference Sara! I never really use PS so i had to do a quick google. Thank you for the advice, i feel much better about this image now.

[swag72]

That's a massive difference  

[steppenwolf]

Huge difference, more of the detail and false colouration that we'd expect to see with this amount of data is now becoming apparent.

[RichLD]

Great result! Just goes to show how very important the processing stage of image creation is.