Lightroom Classic: Black levels/jpeg exports

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I'm having an issue(had that issue for I while) regarding jpeg exports. The black levels from the original file with Lightroom adjustements and my jpeg exports is off no matter what color profile I use. I've tried different export settings but I get a very similar result every time. 
 
This is the histogram from the original file with lightroom adjustements.

This is the histogram of the jpeg export. 

It looks like there is some sort of clipping protection that brings everything back to the center.

It is very frustrating because that clipping is very much intentional, especially for black and white. The resulting jpeg is washed out compared to the preview I get in Lightroom. 

The only workaround I figured out is by doing a printscreen of the photo and cropping it in photoshop. Then I get the same levels. That's just bad !

Please help !
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Cedric Dupuis

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Posted 4 days ago

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Jim Camelford

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Ced, I just tried with a 32-level gradient....and it changed shape slightly...but did not compress like yours.

This is the gradient as a PSD....the PSD is selected (its the left one.....ignore the right one) and you can see the histogram.



I exported it and brought it back as an sRGB JPG.  It's selected and is the one on the far left. Histogram is slightly different - but not compressed.



Maybe you could send me one of yours and I could run it through and we'll see if it's something on your system.  I'm running MAC OS H. Sierra, MacPro.
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Todd Shaner, Champion

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Try exporting to DNG file format. If that also exhibits the issue please upload it to a file sharing site and provide the share link in a reply here. If the DNG is OK please post a JPEG Export file that exhibits the issue. Thank you.

It would help to also proved a screenshot of the Export settings as below.
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Cedric Dupuis

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Thanks for your response Jim. I've tried a similar test as yours and it turns out very similar in the export. However, on a different image from the same set I used in the original post, the same problem occurs. 

Another thing I've noticed is if I import the resulting sRGB jpeg into lightroom, the tonal difference between the original tif and jpeg is very noticable...only in the library module! If I switch between the 2 images in the develop module, they look the same. With the jpeg selected, if I switch between the develop and the library module, you can see the tonal difference. This does not happen with the tif.

I know that the two modules are not using the same color profile(which is puzzling to me), but why does it stay the same with the tif file? 

Almost every web browser(almost every software) use sRGB, but somehow we work in a different color space which we can't export correct tonal values from. I would be more than happy to work only in sRGB if it means I can display the image correctly everywhere. Photoshop allows you to do that, but not Lightroom ? Why, oh why ?
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Cedric Dupuis

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Thanks Todd. Now you've really confused me ! ;) 

I now have 3 images: original TIF with adjustements, DNG and JPEG. 

In the develop module: the DNG and the TIF look almost identical (very small differences) but the JPEG is way off. This is the unwanted difference I'm seeing while viewing the JPEG in other applications such as chrome.

In the library module: the 3 images are different, this time the JPEG and the DNG are closer, but contrast is reduced in JPEG.  

Here is a WeTransfer link with the DNG and JPEG: https://we.tl/t-hvLI81RiIN

Note that this is a film scan from a Nikon Coolscan but I've experience the same issue many times with Raw files from my Nikon D610 editing in black and white (maybe it happens in color but it's less noticeable)
(Edited)
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Todd Shaner, Champion

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This is due to applying excessive sharpening (100 Amount) and insufficient noise reduction (0, 0). It also looks like you may have applied excess sharpening in the film scanner software. These settings should only be made when viewing the image at 100% 1:1 zoom view. I suggest rescanning the negative, reset your sharpening settings and also apply the scanner software grain reduction settings.

https://forums.adobe.com/message/9472696#9472696
https://forums.adobe.com/message/7327718#7327718
LR 1:1 View using your settings in the DNG file


You can "fix" the black point issue with this image file by applying the below LR Detail panel settings. Let me know if you have any questions. I do a lot of film scanning myself using the following "scannerless" film capture. IMHO it's superior to a film scanner. https://luminous-landscape.com/articleImages/CameraScanning.pdf

(Edited)
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Cedric Dupuis

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Thank you Todd ! That was the explanation I was looking for. It makes a lot of sense. The link you provided also explain why this happens very well.

This was a particularly grainy/noisy negative because I used a bad batch of developer. The negatives were very thin so I had to bring it back a bunch. Everything is turned off as far as sharpening or "effects" inside the scanning software. As you said, it's the sharpening in Lightroom that was way too high. (I can now see a tiny variation of tonal values, but nothing unexpected from compression) 

The same problem happens to me with Raw files, but now I'm thinking it's because I was using too much film grain. That may be why it only seems to happen in B&W because I'm trying to emulate grainy emulsions. Maybe I'll try applying the film grain to the resized export to get the same effect without affecting the blacks too much. 
 
Speaking of grain, how much do you think the luminance noise reduction affects it ?  
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Todd Shaner, Champion

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The negatives were very thin so I had to bring it back a bunch. Everything is turned off as far as sharpening or "effects" inside the scanning software.
The film grain is so high in  this image it's impossible to apply sharpening that actual enhances the subject. I suggest using Sharpening Amount 0, Luminance 35, and then apply Clarity and Dehaze adjustments to increase the micro-contrast in the image.

The same problem happens to me with Raw files, but now I'm thinking it's because I was using too much film grain. That may be why it only seems to happen in B&W because I'm trying to emulate grainy emulsion.
If you're using LR Effects> Grain settings I'm not seeing any differences concerning Develop. Library, and Export JPEG files. I tried it with Grain Amount 100, Size 50, and Roughness 50. I exported to full-size and half-size JPEGS and they look the similar at the same size comparison (1:2 and 1:1). You can post an example DNG file if you're seeing something else.
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Cedric Dupuis

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Just tried exporting a Raw image that was giving me problems, tweaked the noise reduction and the black levels came out very nice in the JPEG, with and without the LR grain effect. It was an high ISO shot, so a similar situation as the film scan. This explains why the problem seemed to appear only on certain image sets.

Thank you for taking the time to help, I will definitely keep an eye on these settings in the future ! 
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Todd Shaner, Champion

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Glad to help and hear that resolved the issue. The key is to use 1:1 Zoom view when adjusting the Detail panel settings. With high ISO noisy images it's a fine balance between obtaining good sharpening AND maintaining a low noise level in the image.
A lot of users in the forums will tell you, "The most accurate preview is the Develop module 1:1 Zoom view." That's true because the Develop module uses the less accurate "nearest neighbor" algorithm for creating its less than 1:1 Zoom view previews to prevent control lag. It also uses ProPhoto RGB color space, but very few monitors have significant gamut outside Adobe RGB used by the Library module. The Library module previews also use the more accurate bicubic interpolation same as the Export module.

If the Library module appears near identical to the Develop module at less than 1:1 Zoom (Fit, Fill, 1:16, etc.) view you're good! This provides the most accurate preview of what files will look like when exported and viewed in other applications and by other people (i.e. The Real World).
Sorry for the tirade, but if users understood these LR limitations less of them would be experiencing these type of issues. Enjoy!