Pixelation/Striation/Fringing on Export

[natashav90914735]

Hi, I'm having a problem with a long exposure shot I took.  The sky is looking extremely pixelated when I throw it on any other screen other than my computer I'm editing from (1080P), viewing on social media.  I am aware FB's recommendations of no more than 2048 pixels on the long edge, and even having tried exported accordingly, the sky is still pixelated.  I've tried working with the defringe tools but the problem I'm having is it looks just fine editing through Lightroom and even in my Lightroom library, it is the exported file itself that looks messed up.  I'm attaching pic 1, the quality at 80, no resizing; then pic 2, the quality at 100, resizing to 2048 pixels, though I know this forum is going to lower it even more, but maybe someone just seeing the pic will know what I'm talking about and how to help.  I understand there's a lot going on when taking long exposure.  The original I worked with is a RAW file, checked box for removal of chromatic aberration already.  Thanks.

[Per Berntsen]

I see a little pixelation in the sky of the large image when viewing it at 100%. This is jpg blockiness, caused by the compression. Exporting at 100 quality should remove most, if not all of it.

The smaller image (2048 px) looks perfectly fine when viewed at 100%, no pixelation that I can see.

(and I can view both screenshots full size when I open them in a new tab)

I'm guessing that you are viewing the image at a magnification other than 100% (1:1). 100% is the only accurate representation of the image on screen – one image pixel is represented by one screen pixel.

Different applications use different algorithms when scaling images, and sometimes artifacts will appear.

[Todd Shaner]

I see no actual "pixelation" in either screenshot. Please capture a screenshot on the system that exhibits the issue and then post it here with the system and display information. Most likely the issue is as Per Berntsen  describes due to viewing at greater than 100% screen magnification.

[natashav90914735]

I posted the screen shot you asked for below.  Thanks so much!

[natashav90914735]

Here is the FB screen shot, 2048px on quality at 100

[Todd Shaner]

natashav90914735  wrote

Here is the FB screen shot, 2048px on quality at 100

It looks like FB is compressing the uploaded image file perhaps because it exceeds the maximum file size (MB). Try using the below Export module settings with 80 Quality and then upload the file to a separate FB photo album. Also keep in mind that some people have their display brightness set way too high, which make artifacts more visible.

Forgot to add that you need to make sure 'High Quality' is checked when you create the new FB album.

[natashav90914735]

I believe it does upload to high quality.  I uploaded it outside of an album, just a single photo, but I'll do some test uploads and set to "Only Me" to check it out.  Also, I don't check anything under the sharpen portion, but I noticed your screen shot reply showed that checked.  I read in another forum to not mess with that.  In this case, does that matter?

[Jao vdL]

It doesn’t matter what color space you set in your camera if you shoot raw.

That setting only affects jpeg images. What you are seeing is a limit of

8-bit files and 8-bit display systems. You’ll see if you export to 8-bit

sRGB tif which has lossless compression contrary to jpeg which is lossy

that you’ll still see the steps. They are caused by the bit depth being too

low.

On Fri, Nov 2, 2018 at 9:48 AM natashav90914735 <forums_noreply@adobe.com>

[natashav90914735]

Thanks for your help.  I do not have Photoshop at the moment and I'm trying to understand how this all works.  So I exported an 8-bit tiff and should see the steps more clearly?  I definitely do see them exported 8 and 16 bit tiffs, and then the jpgs as shown above.

[Jao vdL]

This confirms that the steps are not related to jpeg compression. They are a combination of limited bit depth for the 8 bits tiffs and jpegs and of the color management system which uses 8-bit math to show you the picture color corrected. There is unfortunately nothing you can really do about it except for adding a bit of noise to the image which will hide the steps or subtly shifting the color (much harder to do) to avoid these color ranges. Sometimes using a different color space such as adobeRGB or Display P3 can help as they might have better resolution in the range where your color gradient is having issues. Steel colored skies do this very readily in my experience and I often see these posterization effects in night or dusk images. You can avoid them on your own system by using 10-bit monitors with internal LUT based correction but as soon as you go to an 8-bit file you'll have this issue.

[natashav90914735]

Thanks for helping me figure out what the issue is.  I'll try to add some noise.  I already did so many adjustments to color and defringe tools and the original posts above were as best as I could.  It is hard to make those adjustments because on my screen they don't appear at all, so it's editing a slight bit, save, upload to let's say social media, view on a different device/screen or two, then repeat to figure out what helps/hurts.  So to avoid this in the future, I guess I need to get creative in not including night sky on my long exposures?  I don't see this problem in the night sky when it isn't a long exposure.

[Jao vdL]

I wouldn't try to avoid night sky. The gradient has to be fairly specific

and very noise free for this to be a problem.

On Fri, Nov 2, 2018 at 1:16 PM natashav90914735 <forums_noreply@adobe.com>

[natashav90914735]

I think my love of using clarity and dehaze might be contributing to that gradient specific problem.

[Todd Shaner]

Make sure you have all the same LR settings applied before exporting the NEF to DNG file format. This will help with the evaluation and possible solution.

[Todd Shaner]

natashav90914735  wrote

I think my love of using clarity and dehaze might be contributing to that gradient specific problem.

Well no DNG file posted with your edits so I gave the NEF file a try.

Using +25 Clarity and +35 Dehaze along with Basic Tone and some HSL adjustments I was able to achieve similar rendering. Note that I unchecked 'Enable Profile Corrections' to keep the Sky gradient-range as large as possible (i.e. no vignetting correction applied). Exporting the adjusted NEF to 2048 px sRGB JPEG with various Quality settings shows no banding until Quality level 35. I uploaded a 2048 px sRGB JPEG with Quality 100 to Facebook and no banding is visible on my NEC 272w or HP 2509m monitors. I downloaded the Facebook photo and it's about the same size as the 50 Quality JEPG export (see below) so it looks like Facebook is using some aggressive file compression even on 2048 px images. You can download the files at the below Dropbox link. The DNG file has my edits applied for your review.

BTW-You've got some large dust spots in the sky area, which I did not remove. If you're using the Spot Removal tool to remove them it should have no affect on the image rendering.

Dropbox - Facebook Graident Banding Issue - Simplify your life

[natashav90914735]

Thank you!  I know I did check the lens corrections and removal of chromatic aberration, so that must have hurt the image a bit.   I did do spot removal on the dust spots as well.  After critiquing myself I decided to look up others' sky photos, not just long exposure dark skies, but even light skies on social media and see banding on others people's too, so I guess I'm just a perfectionists and FB shouldn't be the platform for my work.  I so appreciate your help!

[Todd Shaner]

natashav90914735  wrote

I know I did check the lens corrections and removal of chromatic aberration, so that must have hurt the image a bit.

Normally you can you leave both checked with no issues. I just unchecked it to eliminate it as a possible source of the banding.

natashav90914735  wrote

After critiquing myself I decided to look up others' sky photos, not just long exposure dark skies, but even light skies on social media and see banding on others people's too, so I guess I'm just a perfectionists and FB shouldn't be the platform for my work.

Given the limitations of Facebook photo posting it's not the best place to display your work. But in general you shouldn't be seeing banding in sky areas of daytime pictures.

I'm beginning to suspect you may have a display issue since even my 6 bit/color HP 2509m isn't showing the degree of banding you describe. Tell us what model system and display you're using and if you calibrate it with a monitor calibrator. Try changing your display profile to the sRGB profile or Adobe RGB if it's a wide gamut display as outlined at the below link. View the JPEG image files I posted on Dropbox and tell me which ones show banding. Next upload the 100 Quality JPEG to Facebook and see if it still exhibits banding. An incompatible display profile or incorrectly adjusted monitor can make it more susceptible to banding.

https://www.lightroomqueen.com/how-do-i-change-my-monitor-profile-to-check-whether-its-corrupted/ 

[natashav90914735]

I saw banding in the first one on your Dropbox, very very faint on the last one.  The display is in sRGB 6-bit, and I saw the banding on the originals I posted not just on this screen, but also having viewed it on the iPad.  The banding on day sky I was referring to was not on any of my images but saying that when I browsed other photographers' FB pages I saw banding on their skies (even daylight) as well, meaning FB compression has got to be a contributor.  Having uploaded the image to my wordpress and viewing it on the same iPad, I see no banding, so yes the contributor is at least definitely the FB compression issue, but then probably even this display, having just realized it is only 6-bit.  I also just looked at my monitor profile.  Considering there was nothing selected, I have now done the steps in the link you posted.  Unfortunately I wiped my Lightroom catalog in my frustration yesterday and so I have to start over in recreated the image I originally posted and now I guess I will see if setting the monitor profile as suggested has a different outcome.

[natashav90914735]

Wiped it, the single image, I meant.  LOL that would be some frustration otherwise.

[Todd Shaner]

natashav90914735  wrote

I also just looked at my monitor profile.  Considering there was nothing selected, I have now done the steps in the link you posted.  Unfortunately I wiped my Lightroom catalog in my frustration yesterday and so I have to start over in recreated the image I originally posted and now I guess I will see if setting the monitor profile as suggested has a different outcome.

No need to recreate the original settings.

You can view and download the JPEG images I uploaded to Dropbox, which were created using my settings with your original NEF file. I suggest doing both online viewing at the below Dropbox link and then download all of the image files and view them inside LR. The only file that exhibits actual banding on my 6 bit/color HP 2509m display is DSC5347_2048 35 Quality.JPG. This was created using the LR Export module with a very low 35 Quality setting.

Dropbox - Facebook Graident Banding Issue - Simplify your life

If you're still seeing actual banding in any of the other files posted above then you have a display issue. Ideally you should use a monitor calibrator, but you can do a basic check using the test images at the below link. Check the Black Level and White Saturation patterns. Ideally you should be able to see the Level 1 Black patch and the White patches below Level 254. There are instructions below each set of test images on adjusting your monitor's controls.

LCD monitor test images

[natashav90914735]

I only see banding on the first photo.  Thank you so much, y'all have seriously gone above to help and give me some understanding.  It was my first time being on here. 

[Todd Shaner]

Good to hear. So to recap the issue Facebook uses heavy file compression that can create banding type artifacts in fine gradient areas (i.e. sky). In addition your monitor did not have a proper display profile assigned to it, which was causing additional banding in those same areas.

I ran a quick check and it appears there's no way to prevent Facebook from applying compression to uploaded image files. I tested this by downloading an image from Facebook that had been compressed. I then re-uploaded this file and the downloaded file size changed from 407 KB to 374 KB. The only thing you can do is to apply less aggressive edits such as I did with your _DSC5347.NEF. Then upload a resized 2048 Long Edge sRGB JPEG with 100 Quality and hope for the best.

Concerning the monitor you can continue to use it with the sRGB profile assigned, but a better solution is to use a monitor calibrator to create a custom display profile. Glad we could we help!

[Todd Shaner]

natashav90914735  wrote

It is hard to make those adjustments because on my screen they don't appear at all, so it's editing a slight bit, save, upload to let's say social media, view on a different device/screen or two, then repeat to figure out what helps/hurts.  So to avoid this in the future, I guess I need to get creative in not including night sky on my long exposures?  I don't see this problem in the night sky when it isn't a long exposure.

If you can post the original raw file to Dropbox or other file sharing site we can take a look at possible LR settings that may minimize the issue. I suggest Exporting the original file to DNG file format, which will contain your LR settings for analysis. Post the DNG export file to the file sharing site. Thank you!

[natashav90914735]

First, you are amazing to want to help me in settings to minimize this.  Here's the Dropbox link for the RAW file.  I'll export the DNG in a moment.

https://www.dropbox.com/s/eeyedqnn4fzt3o6/_DSC5347.NEF?dl=0

[Todd Shaner]

https://forums.adobe.com/people/Jao+vdL  wrote

You can avoid them on your own system by using 10-bit monitors with internal LUT based correction but as soon as you go to an 8-bit file you'll have this issue.

That's not the case for LR, which only supports an 8 bit/color display path. To be honest I rarely see any banding inside LR and even with this image it's barely visible on my NEC 272w true 8 bit/color display panel.