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Bob Somrak
Legend
April 9, 2017
Answered

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

  • April 9, 2017
  • 2 replies
  • 1661 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
    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
    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
    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
    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
    Legend
    April 9, 2017

    D Fosse

    I could understand if you were auto-alining two DIFFERENT tripod shots for instance but this is a RESAVE of the SAME photo and I expected it to be dead-on the first time.  I guess I will just have to do the Auto-Align twice from now on as that seems to work, at least in this occasion.  You would think an operation that is used a lot like ALIGNING would work better.

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