Why the pixelated sky?

[stevevp]

Please see the image below. When I view the photo in Library view the sky is pixelated but not so in Develop view. However when I view the image in my synced collection on the web it is also pixelated. Grateful any advice.

 

[stevevp]

Some time later, I've tried to search again for this problem without success. I've also checked that images appear the same (ie the sky is pixelated) on my iPad so it's not the graphics card on my PC. Any suggestions gratefully received. :thumbsup:

 

[Jim Wilde]

Have you checked the image at 1:1 in the Develop module (which is the only true test, as some extreme sharpening/noise reduction application is under certain circumstances not shown at Fit view in Develop)?

What's the filetype and what are the image dimensions?

 

[stevevp]

Hi Jim,
When I first click on the image in Develop module at 1:1 there is initially some slight pixelation but this then disappears as the image comes into focus. I presume this is just the computer resolving the large image. Thereafter the sky is a bit noisy but not pixelated. The image is a raw NEF at 5868 x 3917, a slight crop from 6016 x 4016. Sharpening is set at 69 and noise reduction at 37.

 

[Jim Wilde]

What happens if you export the file? Does it remain pixelated? Have you tried rebuilding a 1:1 preview of the image to see if that clears up the problem in the Library view?

Those settings aren't overly aggressive (what was the ISO setting?). Yes, what you see in LRWeb is "only" a 2048px jpeg and on the iPad it's a 2560px smart preview, but that shouldn't explain the degree of pixelation going on in that screenshot.

If you would like us to have a look at the image to try to figure this out, could you Ctrl+S on the image to create an XMP sidecar, then upload both the original and the XMP sidecar to somewhere like Dropbox? Then share the link here so that we can download it and try to figure out why this is happening?

 

[stevevp]

Hi Jim,
Many thanks for your further post.
If I export the file it does not remain pixelated. I do not know how to rebuild the 1:1 preview so grateful advice on that please. ISO was 100.

At your suggestion, I have uploaded the files to Dropbox (not done this before so hope it works!) the links are:

Dropbox - DSC_1055.NEF
DSC_1055.xmp

I'd not looked at the original for a while so perhaps, in retrospect, I've just over done it!??

Many thanks again.

 

[Jim Wilde]

Rendering 1:1 is simple....select the image, then do Library>Previews>Build 1:1 Previews. Would be interested to know if that fixes the issue in Library, but still doesn't explain the issue in the mobile ecosystem. I'll have a look to see if I can reproduce.

 

[Jim Wilde]

Steve, I've had a quick look, and when viewing the edited file in Lightroom at 1:1 I see a lot of artifacts in the sky area, almost like a painterly effect. I don't know if you can see what I mean from this screenshot, but you should be able to see it if you look carefully at the sky in your own image at 1:1.


I would think this is the root cause of the problem you're seeing in LRWeb and LRmobile, and it seems to be because you're trying to adjust the image using global adjustments. However, because you've effectively got two different images (sky and earth) you've had to push too hard to try to balance the two. I think you'd have more luck if you worked on two graduated filters (one top down to the horizon, the other bottom up to the same horizon), with a little bit of brushwork along the horizon as needed. Maybe have a look at using a moderate amount of Dehaze as well. I certainly think you'd end up with a much 'cleaner' image which should then eliminate the issues you're seeing in mobile.

 

[stevevp]

Rebuilding a 1:1 preview of the image has solved the problem in Library view but not on the web. I have tried deleting the image from the collection and re-adding it in the hope that it would force some sort of update but the image is still pixelated in the web view. There are a couple of other images with the same problem so it is not isolated.

 

[stevevp]

Thanks for the advice Jim. I will try what you suggest. I might also try just backing things off until the artifacts (which I think is the same as what I refer to incorrectly as "noise" in a post above) might just disappear. It's all a learning curve!

 

[stevevp]

6+ months later I've finally found time to have another good look at this. In the meantime I've tried any number of work arounds including Jim's suggestions of avoiding global adjustments - I'm not sure I understood this as I would have thought that multiple targeted adjustments was more work for LR? Whatever I did, in particular pulling back the extent of my adjustments, whilst I could reduce the likelihood of seeing pixelation or artifacts in LR Classic on the desktop, the synced copy in LR Mobile/CC would always show pixelation. There are about 50 images out of a total of 600 images I took in Budapest which exhibit this. Since starting this exercise, I have moved from PC to iMac and kept LR up to date (still on 7.2) so I don't think it's that.

As a last resort, this afternoon I started yet again, zeroed the image and then synced ie no adjustments at all before syncing. In LR Mobile I added enough contrast, dehaze and reduced the exposure to see the detail in the sky and the pixelation/artifacts were there. What does this mean? Is there a problem with the underlying RAW file or is it something LR is doing?

 

[Jim Wilde]

Where does the image in the cloud originate from? Classic or one of the LRCC apps? If it's from Classic then what you are working with in the cloud is a smart preview, which is much lower resolution than the original raw file and so is far more prone to display issues when pushing the adjustments.

 

[Paul_DS256]

I am not a LR expert but noticed that your exported NEF file you posted above has adjustments in it. Not sure if this is the result of exporting or not. See the attached where I compared your NEF with one of mine.

Since you use a Nikon D750, you may want to ask on the Nikonians User Group. Lot's of discussion on LR.

 

[stevevp]

Hi Jim,
The image in the cloud originates from Lightroom Classic CC (desktop) version. I don't have Lightroom CC on the desktop. By syncing a zeroed image I was trying to work out exactly where the pixelation was occurring. I don't normally edit on LR Mobile but just use it to view my favourite images.

What I am really struggling to understand is why these particular images exhibit this problem. I do like to push some images but have never had this issue before. In the example in my original post, that's what it looks like in LR Classic (and I accept it has been pushed too far). All the images are shot in good daylight at ISO 100. Admittedly most have over-exposed skies to some degree but are otherwise a good starting point.

 

[stevevp]

@DS256 Many thanks for your advice. I'd hoped you'd hit on something but I do not know where the adjustments in the exif data you post have come from - they are not what my camera is set to (I don't generally change the picture control setting from standard) and it's not in the exif for the image in DropBox which correctly record Sharpness +3, Clarity +1 and the others at 0. I couldn't work out how to view the full exif for the edited picture in the original post.

I'll try and have a look on the Nikonians user group but have a feeling my subscriptions has expired. One thing I might do is download Capture NX-D and see what it looks like there.
Cheers. :thumbsup:

 

[Paul_DS256]

@stevevp with respect to "it's not in the exif for the image in DropBox ", it's what ExifToolGUI is reporting in the MAKER section of the metadata of your NEF file. Look at the selected tab. It's not in the EXIF metadata. MAKER metadata is what is set by the camera and are tags from the vendor (Nikon).

You may want to check your STANDARD Picture Control settings. Both you and I had our Picture Control set to standard. In mine, it has a sharpness of +3 set which is what I have set in my STANDARD setup.

Now, having said that. I decided to check since I'm always getting confused on what settings applies to the RAW image vs JPG. Picture Control is only applied to the JPG which is what you see in the viewer as well as what is measured for the histogram. See here.

However, I think it raises an interesting question if the embedded JPG with the NEF is somehow being used for the preview and it is the embedded JPG that is the probem. Goes to the previous point of regenerating the preview.

 

[stevevp]

Using Jeffry Friedl's online EXIF tool I get something completely different for the NEF, as attached. But I am sure you are correct that these settings do not apply to the RAW file. Neither do I think that it is used for the smart preview, but I could be wrong.

I did not get very far with NX-D but have tried to produce a similar edit in Photoshop and am fairly certain it does not have the artifacts. I want to experiment a bit further to confirm that the problem lies somehow with LR

 

[stevevp]

I am still plugging away with this. In the two images below (both exported from LR Mobile), the first image has been edited in LR. In LR Mobile it shows distinct horizontal arcs of artifacts/pixelation in the sky. The second image is the un-edited file with the Adobe Standard profile and no camera or lens calibration. On my iPad the pixelation is just about visible. As stated above, I do not understand why these particular images will not display correctly in LR Mobile even the second one which is effectively straight from the camera and has not been "pushed". I would really like to get to the bottom of this as I am stuck on 50 images which have this problem and would welcome any other thoughts or advice on what exactly the problem with these images is.

 

[Victoria Bampton]

I do not understand why these particular images will not display correctly in LR Mobile

My first question would be whether you're viewing smart previews (the default) or the full quality originals.

 

[stevevp]

Hi Victoria,
I am viewing smart previews (synced from full quality original NEFs in LR Classic on the desktop). I understand - not least from Jim Wilde above - that a smart preview" is much lower resolution than the original raw file and so is far more prone to display issues when pushing the adjustments". What I am struggling to understand is why it is only these particular images which have this issue out of many others which could be considered "pushed" and why there should be any a problem with the flat unprocessed image above which is not being pushed at all? Why is this causing a display problem?
Many thanks, Steve

 

[Hoggy]

Sorry that the thread is a bit TL;DR [that well] for me. But when I saw mention of differences between Library and Develop... Have the differences between color spaces been ruled out yet? I've had/have various images that show pixelated in Library, but fine in Develop - and long-story short, it was down to the different color spaces used between the two : AdobeRGB vs. MelissaRGB, IIRC.

Just thought I'd throw out a possibility to consider...

 

[stevevp]

Hi Hoggy,
Thanks for your response. Can you actually change the colour spaces within Lightroom as I can't find anywhere to do so? I thought you could only change the settings for exporting eg to Photoshop where it is set to ProPhotoRGB. For me the bigger problem/nuisance remains the inability to get the images to display properly in LR Mobile. Fortunately this is just a hobby for me as I now find that the images are equally bad on Adobe Portfolio ...

 

[Hoggy]

Can you actually change the colour spaces within Lightroom as I can't find anywhere to do so?

Unfortunately, you can't change it LR.. I just ended up living with it. Luckily here, not too many photos are affected by it.

 

[Johan Elzenga]

I've seen this too and my conclusion was that this problem is linked to using a custom camera profile in Lightroom Classic. Custom camera profiles are not synched, so it means that Lightroom Mobile can't render this image by itself. It has to use what's available already, and that is apparently only a too low resolution preview.

 

[stevevp]

Thanks Johan. Unfortunately the problem even persists with the Adobe Standard profile - see my post of 3.04 on Wednesday above: "The second image is the un-edited file with the Adobe Standard profile and no camera or lens calibration. On my iPad the pixelation is just about visible."