P: Exporting @2x stopped functioning correctly

I thought that could be it. Very often when you update, preferences get overridden and return to their defaults. Knowing that Adobe had also enhanced its sharpening routine, that was a place to look first.

When I've encountered something not as expected, I first look to preferences. Have they been changed? If not, have they become corrupted? I could wish there were some way Preferences could be more stable, but they're written to disk on exit, and any number of things along the way can seem to scramble them. Not usually all of them, but just enough we haven't a clue what is going on.  '-}

Unfortunately, when I delete preferences because I think they may have become corrupted, I'm usually too involved in seeing if it solved the problem, and then with reconstructing my preferences,  to remember to take my own advice and save out a clean copy of my personal preferences, dated, in order to restore them more quickly next time.<sigh>

Could this be a bug  in PS CC 2017 due to the addition of 'Preserve Details 2.0 Upscale' option? I'm on Windows 7 and don't see any issues with PS Export As 'Size: 2x' so it may be OS X platform dependent.

Improved Image Resize

• Photoshop has an improved image size algorithm designed to detect and preserve the most important details and textures in images when resizing images, without introducing over-sharpening of prominent edges or smoothing out lower contrast details.  In addition to skin tones and hair textures, the technology improves preservation of harder-edged details like text and logos. To enable the technology, choose Preferences > Technology Preview > Enable Preserve Details 2.0 Upscale. Note: when using Image Size, Photoshop uses Preserve Details 1.0 when the Resample option is set to Automatic, even if the technology preview is enabled.

As far as I can tell  the new 'Preserve Details 2.0 Upscale' Resample algorithm is not available in the 'Export As' module. It's only available in the 'Image Size' module.

As Cristen Gillespie suggested try selecting 'Preserve Details' in the 'Export As' Resample selection.

All I know is that I upgraded to PS CC 2018, and continued to use the standard "Export as..." dialog to export assets to multiple sizes—just as I'd always done. Since the update, @15739213 images look awful on Retina screens (or any hi-res screen), when they used to look sharp and crisp. I contacted Adobe Customer Care via Twitter, and they came up empty, and suggested I come here...

That sounds very possible—that both Generate > Image Assets and Export As are front ends to the same thing. But the way you interface with each, without even starting to get into the technical page you suggested, is very different. It's common for defaults to get reset when installing a new version, and the simple one with Export As would be the sharpening when upscaling.

If he is using Image Assets and something in the underlying configuration (not something that most users would ever access) has changed, that's a much bigger deal, something he needs to show Adobe, and something Adobe should probably deal with. To my knowledge, Photoshop users are not expected to write their  own configuration, and it shouldn't have changed without making a note of it.

I believe that the asset generator and the export as both use the underlying generator framework... Just via different entry points, but essentially the same backend.

Maybe someone can correct me if I am wrong?

Why wouldn't he simply be using the common Export As dialog? If he is using Generate > Image assets, I hope he comes back and tells us, as that's a very different process.

Is it possible that the asset generator options got changed? It sounds like the "use-psd-smart-object-pixel-scaling" option is set to True, which would just scale up any smart objects' rasterized pixels instead or re-rendering them at 2x scale.

https://github.com/adobe-photoshop/generator-assets/wiki/Configuration-Options

> Not doing anything differently, nothing else changed expect for Photoshop updating to CC 2018. >

Have you tried changing the method from Bicubic Automatic (default) to Preserve Details? I'm getting results that are just shy of being TOO sharp with Preserve Details when I scale by 2x if the image isn't ideal. I'm afraid I can't test on a 4K monitor, but on a Retina, it's perfect with a good image.