LIGHTROOM 5.3RC: Full Screen Preview from Loupe view applies sharpening incorrectly

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In LR 5.3RC (Windows 7 64), invoking Full Screen Preview from Loupe view applies sharpening incorrectly, resulting in an image that looks much different from Develop or from an exported JPEG. Here's the same photo, from different modes, showing the problem:

Loupe:


Full Screen Preview from Loupe:


Develop:


Full Screen Preview from Develop:


Exported JPEG:


I tried discarding and then rebuilding 1:1 previews, but the problem remains.
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John R. Ellis, Champion

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Posted 5 years ago

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John R. Ellis, Champion

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Another report of similar symptoms:

http://forums.adobe.com/thread/133933...
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John R. Ellis, Champion

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In the other thread, it was suggested that the slightly larger size of the Loupe/Full Screen Preview/Fit image compared to the Loupe/Full Screen And Hide Panels/Fit image might account for the significantly degraded appearance of the former. Perhaps the larger size combined with properties of the downsampling algorithm (e.g. downsampling by a power of 2) account for the image degradation.

I don't think the difference in preview size accounts for the degradation. Rather, I think the problem is specific to the 1:1 previews used for Full Screen Preview.

First, when Loupe/Full Screen Preview is building the 1:1 preview and "Loading..." appears on the bottom of the screen, the image looks exactly the same as Loupe/Full Screen And Hide Panels. Only when "Loading..." disappears does the degraded version appear. This suggests the problem is somehow specific to 1:1 previews rather than a downsampling algorithm.

Second, I tested a number of different size crops of the image along with two different screen resolutions (which determines the height of preview images):



Uniformly, the Full Screen Preview images are degraded, while the Full Screen And Hide Panel images are not.

Note that a Full Screen Preview image displayed at height 1080 is degraded, while the Full Screen And Hide Panel image displayed at the slightly larger height of 1084 is not degraded. So the degradation isn't correlated with increases in preview size.

Also note that the range of reduction for the Full Screen Preview images ranges from 0.197 to 0.230, while the range of reduction for the Full Screen and Hide Panels images ranges from 0.185 to 0.216, a considerable overlap. And none of these reductions are a power of two (a common cause of cause of disparities in preview quality).
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jpowens

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I am not sure, but I think that there is a relationship in what I describe below. Images on the second monitor are NOT the same as the ones on the primary.

The images in the secondary monitor are not the same when switching from Library to Develop modules. While the images on the primary monitor are true to the original the secondary monitor is an interpretation of the image. You can see this if you go to an 4:1 or higher resolution on both the primary and secondary monitors. The primary monitor will show the individual pixels while the secondary monitor will only show a homogenized image with NO pixelation.
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John R. Ellis, Champion

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I think the symptoms you describe are better described by this thread (to which you've contributed):

http://feedback.photoshop.com/photosh...

The symptoms I'm describing here don't involve a discrepancy between two monitor windows and Develop mode, but rather a discrepancy between Loupe/Full Screen Preview/Fit image and Loupe/Full Screen And Hide Panels/Fit.
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John R. Ellis, Champion

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Unlike other reported preview issues, the issue here is a discrepancy between two different Library preview modes, not between a Library preview and Develop, and not between the primary and secondary monitor. And a second problem has surfaced -- after restarting LR, the discrepancy does not appear the first time you invoke Full Screen Preview, only on the second time.

I've verified the problem occurs on two different Windows machines:

Windows 7 64-bit, screen resolutions 2048 x 1152, 1280 x 800
Windows 7 32-bit, screen resolution 1280 x 1024

The problem does not occur on my Mac OS 10.8, screen resolution 2048 x 1152.

Recipe for replicating the problem:

1. Create a new catalog.

2. Import the following raw file:

https://dl.dropboxusercontent.com/u/2...

3. In Develop mode, set Sharpening: Amount to 55 (but the problem is noticeable at 35).

4. Do View > Loupe (E).

5. Do Window > Screen Mode > Full Screen And Hide Panels (Ctrl+Shift+F) / Fit.

6. Do Window > Screen Mode > Full Screen Preview (F) / Fit. "Loading..." appears, and notice how at first the skin and background look the same as in normal Loupe mode, but when "Loading" finishes, notice how the skin and background change to be very grainy. (See the top of this thread for screen shots.)

7. Restart LR.

8. Select the photo and do Window > Screen Mode > Full Screen Preview (F). Notice that the image does not have the extreme grain seen in step 6.

9. Do View > Grid (G) followed by Window > Screen Mode > Full Screen Preview (F). Notice that image now does have the extreme grain.
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John, thank you for posting the raw file and steps that cause the problem. Using your ISO 400 ARW raw file I can see the problem by merely switching between the Develop and Library module Loupe views. It is not necessary to go into full-screen mode with my LR5.2 Windows 7 system to duplicate this issue!

Try this procedure:

1) Open the ARW file in the LR Develop module and set Sharpening Amount = 0, Luminance NR Amount = 0, and Zoom to 1:3 view size

2) Switch to the Library module and go to toolbar Library> Previews> Build 1:1 Previews and make sure the Zoom view is set to 1:3, same as the Develop module. The Library and Develop module's Loupe views should look identical.

3) Go back to the Develop module and set the Sharpening Amount = 50.

4) Switch to the Library module and go to toolbar Library> Previews> Build 1:1 Previews and make sure the Zoom view is still set to 1:3. The Library and Develop module's Loupe views should now look different!

If you see the message 'No 1:1 previews were built' it means LR built the new preview when you switched from the Develop to Library module. This does NOT always happen automatically, so it is always a good idea to select all images (CTRL+A) in the folder after an editing session and manually invoke 'Build 1:1 Previews.' New previews will only be built for the image files that were edited.

I can confirm the same behavior using a Canon 600D image file shot at ISO 3200, without going into Full-Screen' mode. It appears to be due to the issue I posted here in the Photoshop Family forum:

http://feedback.photoshop.com/photosh...

A workaround for now is to use less aggressive sharpening, and/or more Luminance NR. When I encounter this issue it usually means less than the "optimum" Luminance NR settings were used to prevent the effects of noise in Exported images as described at the above report.