navigating images in lightroom develop module is slower in lightroom classic cc than lightroom cc

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  • Updated 5 months ago
I had posted this in the user forums ( ), but posting here because maybe Adobe will see it?

After having an initial AWFUL experience with Lightroom Classic CC post-upgrade from Lightroom CC 2015, I tried to objectively look at some common workflow tasks to quantify the performance degradation that I am experiencing with Lightroom Classic CC.

I have found that navigating through images in the Develop module is much slower in Lightroom Classic CC than in Lightroom CC 2015 - doing the same operation in Lightroom CC 2015 is more than 2x faster than the new Lightroom Classic CC...

Using both Lightroom CC 2015 and Lightroom Classic CC, I performed the following steps:
- importing and building previews.  For this test, I used 70 images from a Nikon D500, which has 20mp images, from RAW uncompressed 14-bit files - the actual files shouldn't matter as what is important is the relative performance in each scenario, and your mileage will vary.  For this action, I performed a drag/drop of the image folders into the Library module window.
- specified a 1:1 preview and smart preview to be generated for the images
- after the import is complete, I selected the first image in the Develop module, set the image view to be Fit. I opened the Basic, Detail, and Lens Correction tabs (ones that I commonly use when editing), with the rest of the tabs collapsed/closed.

- I went ahead and performed some common edit adjustment operations on my images including tweaking these settings:
- increase exposure
- increase contrast
- lower highlights
- increase shadows
- lower black level
- increase clarity
- increase vibrance
- increase saturation
- increase the sharpen mask
- increase sharpening
- increase Luminance noise reduction
- Remove chromatic aberration
- Enable profile corrections

I did this to the first image in the develop module, then synced all the settings through the set to apply the changes to all.  I then waited a short time while the settings were made.

- I then stepped through the images with the arrow keys on the keyboard.  When moving between images,  When moving between images, I moved the next image, then waited until the UI completely finished - when in the Develop module, this seems to be when the "Auto" button in the Tone section is available and not "greyed out."


I found that Lightroom CC 2015 was more than twice as fast as Lightroom Classic CC!  While the percentage varied from my very first experience with the new update, this was closer to the performance degradation that I initially experienced.

LR CC 2015:
develop nav with settings applied:  3:01  (versus 2:06 with no settings applied)

LR Classic CC:
develop nav with settings applied:  6:22  (versus 1:58 with no settings applied)


While the actual numbers will differ based on PC configuration, I believe that the experience will not.  This represents a lof of time where the user has to wait for the user interface to allow the user to regain control, slowing down the overall workflow of the editing process.

Is the Develop module going to get some attention from Adobe to improve this?  Keeping Lightroom CC 2015 on my machine will let me work around the performance degradation issues for now, but have to say this is frustrating...

my PC configuration:

Windows 10
i7-5960x CPU - 8 core, 16 threads
SSDs for boot drive, application, pictures, cache, catalog, etc.
Nvidia GTX-1080 (8GB)
display resolution: 3840x2160 (4K)



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Posted 5 months ago

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Simon Chen, Principal Computer Scientist

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The "Auto" button gets enabled after the Auto Tone values are computed on the image and compare with the current image settings. Lr Classic has made this non-blocking to the main thread (i.e. computed in a background thread asynchronously) whereas the previous version of Lightroom is blocking the main thread. Internally, we use the metric when the histogram/basic controls becomes available, which happens sooner than the update of the "Auto" button.

With Lr Classic CC, you can tradeoff the aspect of the image walking speed with the quality of the initial image preview shown in the develop before the full resolution negative is loaded. You can set the catalog's standard preview size to a lower value (the default is Auto which is the largest screen size for the attached displays). This is particularly helpful if you are using a high resolution display and walking images with settings applied, and if you are able to sacrifice a little bit on the image quality during transition. Prior to Lr Classic, this aspect of the tradeoff is hardwired.


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Hi Simon - Thanks for the information!  It also looks like the image preview is not displayed until after the histogram is calculated, so when the image is displayed, then the UI is ready to go.  That is good to know.

Going through my data set, waiting until the image is displayed takes approximately 2:19, so that seems faster.  I guess I was so used to the blocking that occurred with Lightroom CC 2015.

Any reason as to why the image is not displayed in parallel to when the UI elements are being updated?  That is, why is the image preview displayed last after switching from one image to another? that is, versus being displayed first, then having the UI updated?
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Simon Chen, Principal Computer Scientist

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Good observation. I agree with you in principal.


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My perception of responsiveness is when the image is displayed for me to begin working on it, rather than when the histogram is calculated.  So, currently in Lightroom Classic CC, the UI is drawn, the histogram is calculated, then the image is displayed.  

Lightroom CC 2015 works differently - when I switch from one image to another in the Develop module, the image preview changes almost instantaneously, and then the UI is drawn (sliders are updated, histogram is updated, etc), but as you pointed out, the blocking prevents the user from doing anything until control is returned.

Lightroom Classic CC should work like Lightroom CC 2015, but without the blocking - draw the image first, then update the UI, or at least do both concurrently...  :-)
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Tom de Jongh

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I'm having the same issues.  Only way to speed up processing in the develop module is to restart Lightroom and then it is OK for about 5 or so images when it slows down again.  I have closed all other apps, tried with and without the GPU, updated the graphics driver, disabled plugins and still no joy.  I have lots of photos to process and this is so painfully slow.

Please Adobe, at least acknowledge the problem and tell us you are working on it.  Was there any testing done with this before release?