Lightroom: Develop Auto produces incorrect histograms

  • 2
  • Problem
  • Updated 4 weeks ago
  • Solved
  • (Edited)
Develop Auto can produce noticeably incorrect histograms. To reproduce:

1. Import this raw file.

2. In Develop, click Auto. Observe this histogram:



3. Go to Library, then back to Develop on the same photo.

4. Observe this histogram, which differs a fair bit in the highlights:



Tested on LR 8.3.1 / Mac OS 10.14.5.

----------------------------------

The bug's cause: Auto doesn't set the following Develop settings, which are normally present in Process Version 5 photos:

Brightness = 50
Contrast = 25
Exposure = 0
Shadows = 5

Even though these settings are for Process Versions 1 and 2 and don't normally affect Process Version 5, somehow their absence is tripping up the histogram.

To prove this, insert these steps:

2b. Use  the Show Catalog Metadata plugin to examine the develop settings -- those  four settings are all nil.

3b. Use the plugin to examine the settings again, and notice those settings are now present with their default values.

4b. Use an SDK debugger to remove those settings from the photo, and notice the histogram changes immediately back to that from step 2:
s = targetPhoto:getDevelopSettings ()
s.Brightness, s.Contrast, s.Exposure, s.Shadows = nil, nil, nil, nil
catalog:withWriteAccessDo ("", 
    function () targetPhoto:applyDevelopSettings (s) end)


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John R. Ellis, Champion

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Posted 1 year ago

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Photo of John R. Ellis

John R. Ellis, Champion

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Chinoy Gupta, Employee

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Hi John,

Thanks for reporting this issue. I am able to reproduce it and have filed a bug for this.

Also the Histogram reverts to step 2 when you edit any settings after applying Auto. So it might not be specifically elated to the four settings you mentioned. In any case, we will investigate the issue.

Thanks,
Chinoy
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John R. Ellis, Champion

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"Also the Histogram reverts to step 2 when you edit any settings after applying Auto. So it might not be specifically elated to the four settings you mentioned."

Agreed.
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Todd Shaner, Champion

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I can confirm this issue as well. It may be related to this other report John posted.

https://feedback.photoshop.com/photoshop_family/topics/lightroom-different-histograms-for-identical-...

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Rikk Flohr, Official Rep

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Version 9.3, an update to Lightroom Classic, went live on June 15, 2020 and contains a fix for this issue. Please install the update and respond back if it does not cure the issue for you. Thank you for your patience!
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John R. Ellis, Champion

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I tested the bug recipe in the first post and it no longer shows the bug, thanks.  LR 9.3 / Mac OS 10.15.5.
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Todd Shaner, Champion

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The Auto Tone histogram bug is no longer exhibited on my Windows 10 system with LR 9.3