CS2 Post Processing Technique

[Skywatcher]

The following is a photoshop post-processing technique I developed. I find it very useful at cleaning up uneven background areas of astro images, particularly deep sky. I hope you can follow my  description.


Removing crappy background w/cs2

1 Load Original image into PS- Use The eyedropper tool  to select a pleasing foreground color from the background of the original image.

2. Select all, copy original image, then deselect.     keystrokes Cntl A, Cntl C, Cntl D

3. Select File> New

4. Select the fill bucket and click in the new image frame which will be the background color you selected previously.

6. Paste the original image over the new image frame.    Keystroke cntl V

7. Set blending mode to "difference"

8. Flatten the new image and use levels and curves to enhance the image.

8. It doesn't fix every problem but it does pretty good.


James C
Arkansas

[Ron]

James,

I don't know if I can duplicate the process with my PS Elements or not but sounds like it would be worth a try.

Thanks,

Ron

[keiffer6]

I know this is an old post but I thought I would make note that I find Astronomy Tools Action for Photoshop to be an invaluable help when processing images. They are photoshop actions (basically macros) that perform a number of wonderful tasks to help you get your images looking their best.

They also have them for Photoshop Elements.

http://actions.home.att.net/Astronomy_Tools.html

Well worth the $20 in my opinion.

[Ron]

Thanks for the link Keith.

I still do all of my editing with Photoshop Elements 2 and some tools.  I'll sure check into the actions for Elements since I don't plan on upgrading to Photoshop in the too near future

Ron

[Skywatcher]

I posted the original technique long-long ago. The technique is effective but you may also want to try the following:

Remove Light pollution from astro images

Step 1.  Load the image into Photoshop (I use cs2)
Step 2.  Make a duplicate layer
Step 3.  Make a "new" layer
Step 4.  Select the "duplicate" layer
Step 5.  Use the "eye dropper" to select an area of pollution to be removed
Step 6.  Select the "new" layer
Step 7.  Select the 'paint bucket" tool
Step 8.  click the tool in the "new" layer
Step 9.  change the new layer blending mode to "difference"
Step 10. Merge down the 'new' layer

You are done,find a light polluted image and practice.

It takes longer to explain the technique than it does to do it.

James C
Arkansas