First Ha+RGB image- ngc 3576- REPO

ozstronomer (Geoff) · #1 08-05-2011, 05:35 PM

Hi ALL,

Here is my first attempt at processing a Ha shot with RGB.

Still on L plates with RGB processing but I thought I'd just jump in and try out adding Ha as well

I've add the Ha into the red channel as described on several web sites.

Image details:

Taken with the Moravian G2-8300 and W.O FLT110 refractor
Ha:R:G:B 60:60:60:60 all at 5min subs

I'm not sure if the colour is correct, I've seen some images a little pinker and some with a touch of blue.

Suggestions/comments welcome

Greg, thanks for all the processing tips. I've redone the image and I think it looks a bit better.

Again, Comments/suggestions welcome

Thanks Geoff

multiweb (Marc) · #2 08-05-2011, 05:45 PM

That's very nice . Lovely shot. I think the colors are pretty spot on and the blend looks very natural. Well done.

allan gould · #3 08-05-2011, 06:25 PM

Very nice effort and good detail. However I think it may appear a little more natural if the Ha was blended in as a Luminosity layer rather than in the red .
Just an opinion but may be worth trying.

ozstronomer (Geoff) · #4 08-05-2011, 07:25 PM

Quote:

Originally Posted by multiweb

That's very nice . Lovely shot. I think the colors are pretty spot on and the blend looks very natural. Well done.

Marc, thanks for the reply, still trying to master this new processing so any image is a good one

Quote:

Originally Posted by allan gould

Very nice effort and good detail. However I think it may appear a little more natural if the Ha was blended in as a Luminosity layer rather than in the red .
Just an opinion but may be worth trying.

Thanks Allan, I'll do a repo and try the Luminosity blending as suggested

Ross G · #5 08-05-2011, 08:20 PM

Great shot Geoff.

I love the smooth tones.

Thanks.

Ross.

CoolhandJo (Paul) · #6 08-05-2011, 09:06 PM

Nice shot! Yes, try using Ha as Lum and see what difference it makes. Great image

ozstronomer (Geoff) · #7 09-05-2011, 08:33 AM

Thanks Ross and Paul for the kind comments, I'll try out that Ha blending.

Geoff

multiweb (Marc) · #8 09-05-2011, 08:43 AM

Quote:

Originally Posted by ozstronomer

Thanks Ross and Paul for the kind comments, I'll try out that Ha blending.

Geoff

I actually believe you did the right thing mixing the Ha in the red channel. 70% in red, 30ish% in blue. If you use Ha as Lum you'll level all your other channels but red. One of those nebulae has a dark red patch and the other one is more orange/yellow which you have nicely captured. If you also look at your stars they have kept a nice colors. So your processing is on the money IMHO. The shot is perfect. The only thing I'd do is mirror it.

ozstronomer (Geoff) · #9 09-05-2011, 08:51 AM

Quote:

Originally Posted by multiweb

I actually believe you did the right thing mixing the Ha in the red channel. 70% in red, 30ish% in blue. If you use Ha as Lum you'll level all your other channels but red. One of those nebulae has a dark red patch and the other one is more orange/yellow which you have nicely captured. If you also look at your stars they have kept a nice colors. So your processing is on the money IMHO. The shot is perfect. The only thing I'd do is mirror it.

Thanks Marc, still getting to grips with this RGB,L,Ha processing. Quite a bit different to my previous DSLR work

gregbradley · #10 09-05-2011, 10:45 PM

Something's not quite right here. Your Ha is showing the loops very clearly (they are very faint) yet the main body shows no Ha.

Here is one approach to blending Ha:

1. Do your RGB image.
2. Add your luminance.
3. Create a new layer call it Ha. Make sure it is RGB mode and not grayscale so click on rgb under image/mode/rgb color.
4. Copy and paste the final Ha image you put together already (Ctrl C CtrlV).
5. Click on channels and delete the green and blue channels. Click on green, hold down shift and click blue, then ctrl A and then click on delete. Then click on on rgb again in channels. Now it should be showing that layer as red. Change blending mode from Normal to lighten. Now only brighter pixels will show through and this will protect your stars from attack from the Ha image.

Now if you use curves you can boost the red effect of the Ha only and not the stars.

6. Do the same for Ha as blue channel. Normally though I find only about 10% opacity for that colour is enough. It takes a bit of the overredness off and shows Hbeta emissions.
7. You can create a new layer and copy the Ha there and set it to Luminosity blend. Adjust the slider for opacity to suit. Depends on the image, too much bleaches all the colour out and makes salmon pinks for Ha areas. Perhaps you can use this and perhaps you can't.
Often you can't. It seems to depend on the image.
If you do use it put the luminance layer below the Ha as red layer not above it. The sequence of the layers has an effect on the image as well.

Other approaches are to add Ha to luminance to make a Ha+luminance layer. You need to balance the levels of each and strike the right balance so one is not overwhelming the other.

Greg.

ozstronomer (Geoff) · #11 10-05-2011, 06:24 AM

Greg, thanks for the processing tips,I'll give that a run. There is certainly a difference in processing verses my DSLR

Geoff

Hagar (Doug) · #12 10-05-2011, 12:15 PM

Nice start to the blending whirlpool. It is a lot more complex than we all first think. It can be a real pain to get the blend correct without screwing up the red channel or all colour channels.
I have yet to work it out but will say something just doesn't look right.

Gregs method is the best I have seen yet. Well worth a try.

ozstronomer (Geoff) · #13 10-05-2011, 03:38 PM

Quote:

Originally Posted by Hagar

Nice start to the blending whirlpool. It is a lot more complex than we all first think. It can be a real pain to get the blend correct without screwing up the red channel or all colour channels.
I have yet to work it out but will say something just doesn't look right.

Gregs method is the best I have seen yet. Well worth a try.

Thanks Doug, ""whirlpool"" is quite appropriate as this is a steeper curve than I first expected. Not to be deterred, thankfully this site has many who have gone before and are only to willing to share

cheers Geoff

gregbradley · #14 11-05-2011, 07:20 AM

Give it a go and post the result I am sure there are several of us who will guide you. It will save you a lot of time. Ha blending whirlpool is a good description.

As I recall Doug did a big trial and error of several Ha methods several months ago and knows the ropes. As far as I can tell there are 2 ways of going about it that seem to get good results. One is the method I mentioned here and the other is the blending Ha and luminance into one luminance plus Ha into the red channel (probably a bit harder to do as you may lose some control over the Ha plus it may suppress blue reflection nebula but plenty of excellent image examples using it).

Greg.

ozstronomer (Geoff) · #15 11-05-2011, 03:01 PM

Thanks Greg,

Repo attached to first post for comparision

I'll be interested in your comments

Geoff

bmitchell82 (Brendan) · #16 11-05-2011, 03:17 PM

Geoff,

I actually like your first rendition, the stars are small, the nebula sits out, in the second one I think you have baked it a wee bit to hard, where the stars are now bloated and have lost colour.

A happy medium between them sometimes is a good thing.

My work flow to add in Ha to a image is kind of the same as Greg,

I have pasted a synthetic luminance procedure on my site, though its virtually the same for adding real Ha. where i take the red channel out of the main image and past it into a black and white blank canvas. put a nigh on over processed Ha ontop and set it to luminance, adjust opacity so its not garish but brings your details though nicely.then past it back into your red channel. i go into depth in my guide.

Often you are looking for subtle effects where it sharpens up a certain Ha detail and gives a overall effect. Remember you want to draw attention to areas you want people to see, Try and only have a few of these areas so that your eye doesn't become distracted, too many just over complicates the end image.

http://brendanmitchell.net/?page_id=213
just click on the tutorial and it will take you though the steps

Brendan

Hagar (Doug) · #17 11-05-2011, 03:35 PM

Hi Geoff, The one thing that does stand out in Ha blended images is the difficulty in getting a true red rather than a pastel/pink nebula. The blending method I have been using involves keeping each colour separated and saving them as tiff files for use in Photoshop.

The best way to start is to align all your images and save them as aligned images. This allows mixing an matching in photoshop only requiring very small aligments when you carry out the blend.

I usually start by copying the Ha image and copying it onto both the red and the luminance and the blue channel. Then it is a matter of blending the Ha into each of these channels. I can give you some blend figures but again each image is so different it never ends up where you think it will be. If you start with a normal blend mode and add at say 50% to red, 5 - 10% to blue and 60-80% to the luminance this should be a good starting point. I save several blend options for each colour and mix and match them later.

The one thing to remember or maybe two is:
1 Try to keep all background values much the same.
2 When working with mono images never get the highest value for the image up close to the magical 255 value in photoshop. Once you reach this figure there is no where left to go to and creating images is a game of adding rather than subtracting and you need a little room to manouver your images.

Once I have them all combined and blended i take the blended R B and Lum and the original Green into CCDStack and combine the colours to get a colour composite. You can also do this in Photoshop but I choose to do it in CCD Stack.

It is a bit of mucking about but does work. After you have done it a few times you do get a bit of a feel for how much of each to blend and do find it a lot easier.

Good luck.

ozstronomer (Geoff) · #18 11-05-2011, 04:36 PM

Brenden,Doug

Thanks for the suggestions, when I get a chance ill go back and do repo v2.

Maybe I need to stay with LRBG until I get the training wheels off

Cheers Geoff