combining channels in Photoshop

[Scott]

Hi all,

I've just caught some sii of ngc281 and am wanting to a merge channels with some ha and oiii I collected last yr. The sii was taken with a different setup so I registered them using registar. problem is that when trying to merge the channels in Ps, the merge channels button is greyed out. No doubt it's  something very basic I'm doing wrong but can't for the life of me work it out. Any clues from those in the know? 

Thanks for reading

[Yamez]

you have to create a new document with rgb selected in 16 bits. Then on the new document you go over to the channels and then map your data to whichever colour. Hope this helps

[Scott]

Cheers Yamez. I'll have a go now

 

[Yamez]

Just now, Scott said:

Cheers Yamez. I'll have a go now

 

heres an image if you dont know what i mean

[Davey-T]

Don't you have to convert to 8bit for merge channels ?

Some stuff in P'Shop only works in 8bit.

Dave

No just tried it in 16bit and works 

[steppenwolf]

It is vital that all three images have the same characteristics:-

1. greyscale mode

2. identical dimensions

3. same bit depth - 16 bit is fine by the way

4. ensure that you flatten each image - they must not have any layers

My preferred combination method in PS is to select the 'Channels' Tab, click on the menu button (top right corner of the Channels Tab) select 'Merge Channels', choose RGB and when prompted assign SII to Red, Ha to Green and  OIII to Blue if you are aiming for the Hubble Palette.

Et voila!

[Davey-T]

More flexibility if you use screen blend.

Dave

[Scott]

Thanks all so much. It turned  out I missed the crop step in registar. As I assumed, simple operator error. Thanks to Steppenwolf  for sorting me out.

 

 

[Droogie 2001]

I am glad you have resolved the issue however did you try merging the channels in Registar rather than PS?

I know there is an RGB merge which allows you to combine RGB channels but I guess it would work with what ever you throw at it.

I found Registar to merge channels far better than PS, but that could of course be to my lack of PS skills...