Combining Disk / Prom Images - Another "sticky" please?

[Macavity]

Despite many KIND remarks re. my H-Alpha imaging, I still struggle
significantly with the *combining* of Disk & Prominence images...

Despite my (hey fair enough) "programmer" pretensions, I struggle
with GIMP! Like Dave (Davey-T) I too struggle to remember "What
I did"! A reassuring thought I hope he wont mind me repeating?

I am happy enough that I can individually process Disks & Proms.
I can enlarge / reduce them individually in layers. I can use various
modes of layer combination to align them e.g. "subtracted" etc.

All I really want / need  to do is "blow out" a transparent circle in
my re-sized prominence layer, yet somehow this still eludes me.

I find Michael's guide to Single Pane Processing excellent! Just
the sort of quality / level! Failing this, some equally clear links?  

[Davey-T]

Have you watched these, I think there's a bit on combining proms, Photoshop so not sure how it applies to Gimp.

Dave

http://brierleyhillsolar.blogspot.co.uk/p/imaging-tutorials.html

[Macavity]

Thank you Dave. Certainly a lot of useful stuff to be "going at" anyway!
Knowing "better" (whatever) ways to approach the issue certainly helps.
(Only able to re-invent the wheel so many time in life, I sometimes feel!)

[Davey-T]

By the tenth layer mask, adjustment mask, I tend to glaze over 

Dave

[paulastro]

Gosh, all this sounds terribly technical, I think I'll have to stick to my single frames!  (However inferior they may be )

[Pete Presland]

I have never done a decent combined disc either, but when I do find a technique that works I make sure I write plenty of notes about how I did it. +1 for the Brierley hill tutorials.

[Macavity]

On 5/13/2016 at 16:00, paulastro said:

Gosh, all this sounds terribly technical, I think I'll have to stick to my single frames!  (However inferior they may be )

Oh, I don't think anyone should worry - At least on my account! After a while
one comes to be able to identify the "Artist" by their style here? They are all
FINE by me! Indeed, I often think: "Wow - How does s/he do that"?

Posing the question has at least FORCED me into resolving part of the issue
from a personal , GIMP'er perspective! I would not attempt to comment on
the INDIVIDUAL processing of the disk and prominence images, but I have
now discovered one way of *merging* the two...

To me, the SIMPLEST way of combining the Disk & Prom images is to render
the background of the Disk image *transparent* and superimpose it over the
Prom image. What I was "forgetting" (and my frustration) was that, to create
a transparent background, one needs (too add) an "Alpha Channel".

Once done, I simply made a circular selection of the disk (to pixel precision!)
and REVERSED this (to select the background) and then use "Edit > Clear"
to change the background of the Disk to transparent! Superimposing this
(via layers), resizing / positioning it appropriately, over the Prom (layer), 
I leave as an"Exercise for the reader" (lol).

Just for FUN, I wanted to have a yellow Photosphere + RED Prominences.
To achieve the former, I used (colour) "curves" - Not forgetting the Disk
image has to be RGB rather than greyscale? Another sometime frustration!
(To convert between Greyscale and RGB (if needed) use "Image > Mode")
To render the whole prominence layer RED, I finally remembered to use:
"Colors > Colorify" rather than the wimpish "Hue and Saturation" etc.

Whatever the quality of the individual Disk and Prom Layer, (I ask you
to ignore that part!) I can now get what I wanted in the combination:

This is in NO WAY intended as the "sticky" lol. There is ever "room for improvement" 
and a few "Cans o' Worms" opened! But the BASIC idea now works better form me! 

P.S. Currently thinking a bit about how I might retain more of the detail in Proms...
I often tend to BURN OUT most of this! Since I won't have to use "drifting" to remove
Newton's rings, I'm considering using multiple images... "Contrast Blending" even?