How to Create Synthetic Green Channel??

[whixson]

Hi! I've taken some narrow band bi-color images of the Veil in Red (H-A) and Blue (O-III). I'd like to blend the R and B to create a synthetic Green and paste it into the G channel of the LRGB module.

Also does it make sense to create a synthetic L channel with the data I have?

[admin]

Hi,

The LRGB module by default will already create a synthetic green channel for you if you load the red and blue channels with data (you can switch off this behavior as well).
If you require anything else but a 50/50 blend for the green channel, then you can create your own blend using the Layer module by loading the two frames (as grayscale) in the fore/background, set the blend amount you require and save the result. You can then import that result as your green channel in the LRGB module.

It may be useful to create a synthetic L channel if your Ha/OIII stacks are of different total exposure lengths, else your L will be a 50/50 mix of signal from Ha and OIII.

Does that help?

[whixson]

That's great Ivo. Works like a charm, although I did have more O-III data than H-a. 190 minutes vs 160 minutes respectively. And the H-a data is noisier and not as clear and that shows in my image when I processed it. What isn't clear is if I layer them and weight them, which way? Seems like you might want to weigh the H-a heavier to better balance it? Or do you weigh the O-III heavier, specifically 190/350?

Thanks again,

Wayne

[whixson]

Here's a link to the image. Primary processing in ST with color tuning in Lightroom

http://spaceweathergallery.com/indiv_up ... qm3k68ceg3