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HaRGB Processing Help Please!


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I've only done one RGB (LRGB in that case) with images from my Atik, using Olly Penrice's instructions, and it did really well. That was a galaxy. Now I'm trying to process HaRGB of the Wizard Neb, but the colour and stars look awful. The colour looks pink even when I line up the channels, and the stars have aggressive halos.

I did 10 x 8mins Ha, and 2 each of R, G and B, 2x2 binning, 8mins.

Can you all have a go for me? Please tell me what you did! I hope this then becomes a sticky for others who are having problems!

Here are the TIFFs:

Ha:

http://www.mediafire.com/view/t25ndg0ahcq8a6l/Wizard_Ha.TIF

Red:

http://www.mediafire.com/view/bo8hdhatlsp45uq/Wizard_Red_enlarged.tif

Green:

http://www.mediafire.com/view/o5yvyihd7xty7c9/Wizard_Green_enlarged.tif

Blue:

http://www.mediafire.com/view/37dnnp3tcunjc3g/Wizard_Blue_enlarged.tif

Many thanks!

Alexxx

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This is my rendering.

I left the edges as they were to show the alignment of the various filters.

I combined the RGB together in the usual manner, i.e. making a duplicate of one layer, converting it to RGB and then pasting the different RGB filters into their relevant channels.  I then duplicated the layer and stretched the lower layer only to stretch the nebulosity and not so much the stars, and then erased part of the the upper layer using the rubber to reveal the nebulosity in the lower layer and then flattened.

The main problem is the difference in sizes between the stars in the different filters, and for this I followed this tutorial:

http://starizona.com/acb/ccd/software/ps_hargb.aspx

Having almost erased the stars in the RGB I pasted over the Ha layer as in the tutorial.  

I then increased the colour in Match colour and re-posted the Ha layer over the top once again (as we lost some detail in the starizona Curve) adjustments.  Then adjusted the colour layer in curves once again.

Fiddled with selective colour until I got a combination I liked best.

I am sure there are many ways to crack an egg, but this is my method.  It still looks a bit pink, but if I increased it any more it didn't look too great.

Oh and finally I rotated the image as I find it difficult to do upside down ha ha.

Carole 

93a74193cdac619a010aeb774218fd68.1824x0_

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Hi Carole,

Having a look at this now. I don't get your explanation:

"I combined the RGB together in the usual manner, i.e. making a duplicate of one layer, converting it to RGB and then pasting the different RGB filters into their relevant channels."

Please elucidate!

I used the following method I was given, but I'm not having much luck with:

Open the three mono image TIF files (Red, Green and Blue)

Open the Channels palette by selecting Window - Channels. Click on the Channels palette menu and select 'Merge Channels'. Select 'RGB' from the drop down list box, set 'Channels' to '3' and click on 'OK'. Using the list box, specify which file applies to each of the three colours and click on OK. Your RGB colour image will immediately appear.

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I dont do HaRGB very often, but the way I approach it is to copy the red channel to a new document - paste in the Ha, and blend it at something like 30-50% (blend mode lighten), merge, then paste back into the RGB red channel. I also then add a bit of it to the luminance too (it helps match the star sizes a little better and brings down the noise). Noels "make stars smaller" helps a bit - but if you dont have that then you can use a layer mask to do it manually.

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Hi Alex,

Is it just the combination of RGB that isn't working for you?

This is the method which I use explained by Anna Morris:

http://www.eprisephoto.com/create-lrgb

I dont do HaRGB very often, but the way I approach it is to copy the red channel to a new document - paste in the Ha, and blend it at something like 30-50% (blend mode lighten), merge, then paste back into the RGB red channel.

I often use this method too.

Carole 

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I used the following method I was given, but I'm not having much luck with:

Open the three mono image TIF files (Red, Green and Blue)

Open the Channels palette by selecting Window - Channels. Click on the Channels palette menu and select 'Merge Channels'. Select 'RGB' from the drop down list box, set 'Channels' to '3' and click on 'OK'. Using the list box, specify which file applies to each of the three colours and click on OK. Your RGB colour image will immediately appear.

I find this way of combining an RGB image the easiest by far. It does however depend on starting from the right place......

1) stack your data in the normal way........ I use PI, but DSS does it. 

2) you now have 3 images 1 - The red channel data, 2 - the Green channel data and 3 - the blue channel data

3) You now need to align these - I don't know if DSS does this (again I use PI) but you need to make sure that the 3 subs are aligned and that the stars are in exactly the same place so that when you combine them you have the red, green and blue of each star in exactly the same place ...... Does that make sense?

4) Open each aligned channel data in PS - So you will have the red channel image, green channel image and blue channel image open.

5) Open the Channels tab (can be accessed via the 'windows' menu along the top.

6) To the right of that tab, there's a small square box with horizontal lines - Click that.

7) Click 'merge channels'

8) Select RGB under 'Mode'

9) Then you can place the appropriate image into the corresponding channel and press OK.

Hope that helps.

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Firstly, think through what you're trying to do when adding Ha. Ha is red so, in my book, it belongs in the red channel, not in the luminance. So that's where I put it.

The RGB image is fully processed. The Ha image is fully processed and aligned to the RGB. Now as Rob says, it's a good idea to add the Ha to the red channel in blend mode lighten. Why? Because in this mode the Ha is applied only where it is brighter than the red. Your Ha stars will be smaller and fainter than your RGB so they won't be applied to the red stars - which is perfect. Their colour won't change. Bingo.

Now how much Ha should you apply? Impossible to say because it depends entirely on how strong your Ha happens to be relative to your red. Once you have Ha pasted onto red in Blend Mode Lighten use the eyeball to blink it on and off. Does it do anything? If it does quite a lot then don't worry about over-applying it, we'll fix that later. Just flatten it and merge your channels with R in R, G in G and B in B. If it doesn't do much, or doesn't do anything (as was the case in my last image, VDB152) you have to make it behave! So, still in blend mode lighten with the ineffective Ha over the red, give the Ha a big lift in Curves, trying not to lift the background sky too much, so pin the bottom of the curve. Eventually the Ha will start to affect the red channel. Give it plenty of welly and flatten it and merge channels. (If you were to look at the Ha image after this monster stretch it would look awful and full of noise. But where is the noise? In the faint stuff and blend mode lighten doesn't apply the faint the stuff. Second Bingo!!

OK so now you feel, maybe, that there is too much Ha in the image? Not a problem, madame! Paste the HaRGB on top of the RGB and adjust the opacity until you like it. Surely this is an easier method than the usual recommendation of adding Ha a little at a time?

A tip for popping Ha in RGB images. Ps, Image, Adjustments, Selective Colour, Reds, move the top slider to the left. You'll love it!

Olly

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Um, Olly, I've tried this but can't get my head round it. I've processed the RGB, as you said, so they're all in one image. My Ha is processed.

I made a new doc with the red and added the Ha in Lighten, at 50%. That's when I get confused. You mention ' . . . merge your channels with R in R, G in G and B in B.' But I've already done that with the pre-processed RGB image.

You go on to say that I should do a strong Curves. Is that on the new doc with just red and Ha?

But then you say 'Give it plenty of welly and flatten it and merge channels.' So that suggests I should have copied the red + Ha new image to the red channel in RGB.

Sorry I'm getting confused. I get like that!

Please help!

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Ok..... how about this......... This is how I do it.

1) Take your RGB image and save it so that you know where it is

2) Go to the channels tab.... and split the channels. This will give you three seperate images - each one has a R, G or B ending so that you know what is what.

3) Take your already processed Ha image

4) Click on it so that it's current - Copy it - Ctrl C

5) Go to your Red channel image

6) Paste the Ha into it - Ctrl V

7) Click on the layers tab thats in the channel box and you will see background as the original red and layer 1 is your copied Ha.

8) Press the little eye on the background so that's not in use and click on layer 1

9) Open your curves and stretch the Ha - Don't clip the highlights, but you do need to push it.

10) Click on the eye of the background 

11) On Layer 1, go to the blending options in the little box and click 'lighten' - This will ensure that the only detail that is showing over the background beneath is stuff that is lighter.

12) Flatten the image - Ctrl E or do it through the main menu across the top 

13) Go to the menu at the top right of the box (little horizontal lines) and click merge channels

14) Select RGB mode and OK

15) Put the right channels into the right section

Now you will have a very red image. Open up your previously saved RGB image, copy and paste it into your newly merged image (Ctrl C and CTRL V) and then select the opactity that you like of the newly created HaRGB image over the original RGB image.

Hope that helps.

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Sorry, Alex, to go through every step is very difficult. When things calm down for me with the business, which will be when bookings ease off in November, I really will try to produce some video tutorials. I'd like to do this. I don't pretend to know all there is to know about adding Ha but I do have some ideas which may be outside the mainstream and the best way to demo them is via video. The big problem is that every image is different so you really need to start with an understanding of what the graphics programmes are doing when you use them. When I get to the video tutorial stage (and I'm a software numptie, I really am) I'd be delighted for you to beta test my explanatory efforts!

Olly

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Thank you Olly, Sara.

Sara, I'll have a go with your tutorial today.

Olly, good luck! I'd be delighted to test your tutorials! I'm a bit of a sw numpty too. I wish I understood more of why I do what I do in PS. I do understand much more than I used to, so it's coming!

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OK, so the RGB channels were already split, plus an RGB channel.



post-1704-0-50472900-1439717833_thumb.jp



I selected the Ha, copied and pasted it onto the Red channel:



post-1704-0-89686600-1439717847_thumb.jp



But when I go back to the Layers tab, there's no new Ha Layer.



post-1704-0-45274700-1439717862.jpg



Stumped at the first hurdle! I know it's something I'm doing that's daft.


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