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Bob Somrak
Bob Somrak
Legend
April 9, 2017
Answered

I have to Auto-Align Layers twice to make it work correctly

  • April 9, 2017
  • 2 replies
  • 1712 views

I was working on a problem and discovered this issue.  I have a PSD file.  I "Save As" the PSD file as a TIFF so they should be the same.  Put the TIFF on top of the PSD and chose Auto-Align and set the blending mode of the top Layer to Difference and got this.

I selected the layers AGAIN and chose Auto-Align AGAIN and this time it WORKED as I got this as the Difference.  A perfect match.

I tried this on a couple other photos and got the same results.  Seems like the Auto-Align doesn't EXACTLY align the first time you use it.

      This topic has been closed for replies.
      Correct answer D Fosse

      If you use auto-align a lot, you will soon discover that the result is frequently offset by 4 or 5 pixels. Once nudged into position, the match is usually perfect - so it's not that the algorithm itself doesn't work. I'm willing to bet that's what happened here.

      The offset appears random and can go either way, often diagonally, such as two pixels right and four up.

      I've no idea why this happens, but I always factor that in. Once completed, I go to 100% and nudge into place. Only then do I run auto-blend if that's the next step.

      This is also one reason I never use Photomerge.

      2 replies

      AdamB82
      AdamB82
      Participating Frequently
      December 13, 2021

      Any reason these bugs aren't being fixed and auto-align is just being left buggy?  Why does auto-align still not work at the end of 2021?  Is there any roadmap for updating auto-align to actually work for things like hand held images?  Microsoft ICE passed photoshop in auto aligning about 10 years ago, will Adobe try to compete again on this?

      enrique.leopard
      enrique.leopard
      Participant
      December 18, 2023

      I am trying to align 24 images loaded as layers. They are 1920x1080 px. If i check Geometric Distortion Photoshop never finishes to process.  So I use only AUTO. After one pass layers are align very badly. After applying auto.align again the result is much better!  doing it a third time makes very small difference... Now it is december 2023 and i am using PS 25.3.1.   Wish this featue could be improoved. I do a lot of Longterm timelapse and use this to corret cameta movement.

      D Fosse
      Community Expert
      D FosseCommunity Expert
      Community Expert
      December 18, 2023

      Correct, the pixel alignment is often not perfect.

       

      But don't run it again! It's just a clean pixel offset. Rerunning it gets you another round of resampling, and you don't want that.

       

      Press ctrl+1 to get 100%, then use the arrow keys to nudge into position, one by one pixel.

       

      I agree, this should be fixed. It's been reported here many times. But in the meantime, just nudge to get the best result.

        Trevor.Dennis
        Community Expert
        Trevor.DennisCommunity Expert
        Community Expert
        April 9, 2017

        What options did you use when saving the TIFF file?  I would have expected that if you have compression set to None, it would save an identical version.

        D Fosse
        Community Expert
        D FosseCommunity ExpertCorrect answer
        Community Expert
        April 9, 2017

        If you use auto-align a lot, you will soon discover that the result is frequently offset by 4 or 5 pixels. Once nudged into position, the match is usually perfect - so it's not that the algorithm itself doesn't work. I'm willing to bet that's what happened here.

        The offset appears random and can go either way, often diagonally, such as two pixels right and four up.

        I've no idea why this happens, but I always factor that in. Once completed, I go to 100% and nudge into place. Only then do I run auto-blend if that's the next step.

        This is also one reason I never use Photomerge.

          Bob Somrak
          Bob SomrakAuthor
          Legend
          July 24, 2018

          Bob, I have tried this a few times just to test, and I am always getting a perfect result.  I use the Difference trick when stitching multiple panels of topo maps, and always do it manually, because of the small overlap.  So  I am not sure what to suggest.  You are right that you shouldn't need more than one go to Auto Align, and Dag appears to back up your experience that this is sometimes necessary.


          Thank you Trevor for the reply.  I only did a couple stacks today the first time since a year ago and neither worked "perfect" the first time but did ok on the second try as I indicated above.   I will be doing several in the next few weeks so hopefully I will have the good luck you did.  I just decided to do the alignment twice every time to try to avoid the problem.  The photo that started the thread was a TIFF that was a derivative of the PSD that was essentially exactly the same.  I was doing this to try to help a user that was having issues with exports of PSD files in Lightroom on the Lr forum and that is how I discovered the issue. 

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