Remove seam on composite photo

[mhump]

I took two pictures of the night sky and I am trying to stich them together to make like a sort of mosaic/vertical panorama.

I'm pretty new to Photoshop, and wondering if there is a way to remove the seam accross the middle of the photo.  There is some vignetting, but mainly i'm trying to get rid of the harsh horizonal line.  So far everything i've tried makes it look worse.

[George_F]

Ideally there would be some overlap between the first two layers (layers 3+4).  Then use a layer mask with the brush set to 1%-5% flow to paint black along the seam to feather it, and you should be good to go.  Let me know if any of that doesn't make sense!

Cheers

[Trevor.Dennis · Accepted solution]

Are the two layers part of a photomerge, or are they unrelated?

Even if the latter, I'd be inclined to try selecting the two layers, and going Edit > Auto Blend Layers

I have no idea if this will work if the layers are not part of a photo merge.  The problem, as you are finding, is that the difference is not consistent, which makes masking really difficult.

I'd be inclined to try the dodge and burn tools, but make sure you have the right tonal range selected, as the results look muddy and nasty if you have it wrong./

Ctrl click the layer to load it as a selection before using dodge and burn.  That restricts changes to where you want them.

I'll be interested to hear if Auto Blend does anything?

[mhump]

I'm not totally clear on what you mean by "photo merge".  Basically, I took the picture that is the bottom half, then tilted my camera up a bit and took the picture that is the top half.   I was doing this by estimate in the dark.  The top edge of the bottom photo is at about the middle of the top photo.  It took me many tries just to get the colors to be remotely close.  I guess this is because the lights from the barn?  not sure.  But the top half (which was stars/sky only) was much darker and grayer.  The other thing is the vignetting... The top edge and corners of the bottom picture is dark from the vignetting.  Then I'm trying to match this with the middle of the top photo, wich is the brightest portion.

Anyway, I appreciate everyone's suggestions and I will give them a try.

[mhump]

For some reason it never occured to me to use the Auto Blend/Align features in Ps.   I've used those before for Panoramas, but figured there was no way it would be able to aling these photos because of the distortion.  But after your suggestion, I decided to give it a try.  

As I mentioned, the two photos had very different color/white balance.  The Auto-Align worked in about 2 seconds.  The auto-blend, however, kept trying to match the bottom photo (with the barn) to the top, and the whole thing came out looking washed out and gray.  

So I put both photos in lightroom and and did some adjustments on the top photo to try to match the bottom as close as I could, then repeated the Auto-Blend/Align processes in Ps.  I am very pleased and pretty impressed with the results.  You can still see a bit of a shadow accross the middle, but I will keep working with it.

Overall, this is what I was looking for.  No doubt a Ps pro could get better results, but this is more or less what I was trying to accomplish.    

Thanks again for your repsones and suggestions. 

[George_F]

@mhump Also, feel free to post the files for others to attempt if you are interested.  It's not uncommon for us to edit examples and show layer panels.  From what you describe, I do this sort of edit often.

[mhump]

Hi @George_F - I would be curious what someone who knows what they are doing could do with these.  I am learning this as I go, and trying to figure out how to improve the image acquistion as well as the processing.   Sometimes I'm not sure if it's as good as I can get with the photos I took, or if better processing technique would yield significantly better results.  

For these photos, I took 150 images of each frame, and used Sequator to stack them.  These are from a Canon R with a 50mm 1.8 lens (Shot at 7 seconds, f 2.0).  Using a tripod of course, I took the bottom frames (with the barn), then tried my best to tilt straight up to capture more of the sky/Milky Way.

The original files are too large to attach to this post, so I've made them available on OneDrive.  I've uploaded the two un-processed/un-editited images that were produced by Sequator.  If you (or anyone) would like to give it a go, I would find that interesting.  

Original Image Files

[George_F]

Perfect!  I'll take a stab at it when I get a chance.

Cheers