Help: Image Banding / Posterisation when uploading to Social Media (Twitter)

[Colourwrks]

Hi guys,

I am having an annoying problem with image banding / posterisation and need some help from you experts.

The image was shot in RAW using a 20mp Mavic Pro 2 Drone.
Raw file processed using TopazLaz labs for sharpening and AI denoise applied
Image processed in Lightroom.
Light adjustments applied (Exp+10, Contrast -10, HL+5, Shadow+5, White+5, Black-5, Clarity-10, Dehaze 0, Vibrance +25, Saturation 0)
S-Curve to overall Tone Curve
S-Curve to each RGB channel
Dark gradient from bottom to middle of the image.
Colour grading with HSL 
No caliberation
Working in 16-Bit on both Lightroom and Photoshop

The image looks fine in Lightroom CC
The image looks fine on export using Macbook Pro M2

When I upload the image to Twitter im getting problems.  It looks like Twitter is compressing the image and horrible banding is appearing in the right hand corner. I have tried multiple ways of exporting the image such as:

JPEG 100% Fullsize ProPhotoRGB (via Lightroom)
JPEG 100% 2048 Long Edge ProPhotoRGB (via Lightroom)
PNG 100% Fullsize ProPhotoRGB 16 Bit (via Lightroom)
PNG 100% 2048 Long Edge ProPhotoRGB 16 Bit (via Lightroom)

and via Photoshop

JPEG 100% Fullsize Bilinear 16 Bit(via Photoshop)
PNG24 100% Fullsize Bilinear 16Bit (via Photoshop)

I wouldnt usually let this concern my but im releasing this image as an print and digital NFT so obviously I want the image displayed online to my audience be representative of my quality of  work.

Ive searched online and there seems to be some methods of removing banding such as Gaussian Blur and Adding Noise but the image displayed in Lightroom and Photoshop isnt showing the banding which makes me question is the banding even there? Only after uploading to social media it appears. Is there anything I can do to work round this? 

Image uploaded is exported as an JPEG 100% full dimensions from Lightroom.  Ive tested almost 20 variables.

Thank you for any help or advice!

[Colourwrks]

Image attached

[Colourwrks]

Hopefully these screenshots help explain whats going on:

One screenshot of the image displayed in the Iphone Photos App - Looks fine.
One image showing image uploaded and posted to Twitter showing horrible banding 

[Ian Lyons]

I've never used Twitter. Nevertheless, based on the info you've provided, I think you've answered your own question. The issue is due to the way Twitter is compressing the file.

[D Fosse]

That's what I said in the Photoshop forum, where this was also posted.

[Colourwrks]

I wasnt sure whether to post it in the LR or PS Community.  Moderator feel free to delete one.

[Colourwrks]

Thanks. Im still investigating.  It seems adding gaussian blur and a noise layer helps but again its when uploading the banding seems to appear.  Very frustrating.

[D Fosse]

The blur is wasted, it won't help. The banding happens later, on the receiving end.

But a little noise should take the edge off it - just make sure it's applied to the file at final size if you scale it down for posting. If the file is scaled down by the website from your original, the noise won't be as effective.

This is basically a problem with all social media-type websites. You never know what they do to your original file.

One trick, is to take a screenshot from your browser and open it in Photoshop. Crop it to the edge pixels of the image, and then you know the size it will end up at. Then you can prepare your file at that pixel size. Assuming it's fixed size and not responsive design where it scales with browser width.

[Jao vdL]

You really need to export to sRGB or displayP3 instead of prophoto. You also should scale your images down before uploading to twitter. You will also get better results when you use a lower quality setting (yeah I know this doesn't make sense on the face of it but it is true). The whole game is avoiding that twitter recompresses the image, so use the correct resolution. You do NOT want to go over 1600x900 pixels or it will always get scaled and recompressed using very low quality algorithms. For square images the size is actually 1080x1080 and for portrait images only 1080x1350! You can go bigger but twitter will rescale the images. You also do not want the file you upload to be bigger than 5MB. About 1MB is ideal.

So the way to get good quality on twitter is export at 1600x900 pixels. Use display output sharpening. Use sRGB (or display P3 if you mostly mostly expect to be viewed on iOS and Android devices and not web browsers), use jpeg quality of about 85. This will get you the highest quality image on twitter. Anything else will get butchered. You can trick it by using png but it will need to be scaled down to the sizes above and again no bigger than 5 MB.

Social media is just not a place to expect high quality images.