Method for aligning and combining individual red, green and blue images into single RGB image in Photoshop CS6

I worked out a method for aligning individual red, green and blue images and then creating single RGB image in Photoshop CS6 when I was processing my comet picture yesterday – there is probably a better one – so if you know it please send it to me!


(1) Load up the 3 individual colour images into CS6

(2) Copy the green and blue images onto the red image as new layers (for each image – select all then copy on image then click on red image, create new layer, then highlight layer name and then click <paste>)

(3) Change the transparency on each of green and blue layers to 50%

(4) Switch off green layer

(5) Click <move> and move blue layer until feature (comet, moon, etc.) is aligned with red layer.

(6) Switch off blue layer and switch on green layer.

(7) Click <move> and move green layer until feature (comet, moon, etc.) is aligned with red layer.

(8) Now all three layers are aligned

(9) Ensure all 3 layers switched on

(10) Select top layer – now crop the image to remove excess borders – this will automatically crop the other 2 layers as well.

(11) Save you Photoshop file as Photoshop proprietary format.

(12) Duplicate this file – so three copies – call then red, green, blue.

(13) In turn, load up each copy into CS6 and delete 2 layers so that the only layer that remains on each copy is the one that matches the name – e.g. the file labelled “red” only contains the red layer. Then select that layer, right click and flatten image for each file. Finally, save as TIFF file. This means you now have three aligned and cropped TIFF files – “red”, “green”, “blue”.

(14) In Photoshop, use Nol’s actions to create RGB file – works well.

3 Responses

  1. Don’t know how much it costs these days. I was lucky, I got it free. You can also control the mount using Maxim DL and process the images. Possibly might be worth just having a look at it. See if you can find a free version.

  2. Andy,
    It all sounds complicated I know, this is the method I used to use myself.
    It works very well when the subs have been taken in the same session. The problems come when there are a few days or more between imaging, then not only do you get linear movement (fairly easy to correct) but also rotation.
    I have found an alignment tool in Maxim DL which does the job automatically after you have selected 2 stars (the same stars!!) in each image ( I choose them in opposite corners ). works a treat.

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.