If it means one that everyone uses then none.
Even if you simply import a .psd and re-export it again as-is, it will still break things like smart objects and layer blending options.
It's not Krita's fault: .psd is not an interchangeable format. Implementing .psd support perfectly is basically implementing the whole PS itself. It's all the artists' "fault". But it doesn't change the fact that using Krita makes my days difficult.
I've once seen a .psd that won't display correctly in neither Ps or CSP, supposedly because it was exported from something else. That didn't seem like a fun situation.
It’s a 30+ year old format that went to multiple transitions. I don’t envy the poor soul that has to reverse engineer it.
This one? https://github.com/gco/xee/blob/4fa3a6d609dd72b8493e52a68f31...
https://github.com/gco/xee/commit/750196023da5457d9535b30299...
Or maybe the huge goliath that gives less than 0 shits about interoperability makes it difficult?
I'm not saying it's not a great app (I'm not familiar with it enough to judge it). But if I'm not using an open source one, I'd use the industry standard one.
Last time they had a sale on their "Universal" bundle, which got you Mac, Windows and iPad licenses for all their products for $100, I had just received some illustrator files that I wanted to work with on my desktop and decided to go ahead and pick that up.
I now find myself using Photo and Designer instead of Krita/Gimp and Inkscape, because I'm more efficient with it as a non-expert user and because the .psd and .ai interop is better.
I need to deal with one of those two file types approximately 0.75 times a month, so the industry standard one feels eye-wateringly expensive. But a one-time $100 fee for a less frustrating experience than the open source ones offered felt worthwhile to me. And they've grown on me to the point that I pick them up when I need to make something for a game jam, not just when I need the interop.
There's a handful of other programs that one or two of my friends use but absolutely zero of my friends have talked about using Affinity Photo.
M$ Windows, Photoshop, each company gets locked into their own CAD nightmare.
On the flip slide, we have Blender, Linux Server, (enough)SQL, Git, Stable Diffusion, and maybe python/python libraries if that counts.
The most surprising thing is how little professional people get paid, again compared to web dev.
They pay less because they can - there are many more highly motivated people who dream of making video games than there are open spots.
People are less highly motivated who dream about making Another Corporate CRUD App 2.0 (this time with Firefox support), and there are a lot more job openings.
If I had had the same level of understanding of economics as I do now, I probably would have stayed in web backend development.
The phenomenon of open source tools being able to even be considered by professional development is a very recent phenomenon (in the grand scheme of things). But for programmers it's still difficult because console support is so important and still extremely closed down.
It would be really cool to have some kind of open source community that developed these kinds of "usage specific" plugins across multiple open-source projects, to kind of patch in that functionality where it's missing. Some people to work on ever-evolving interfaces for the supported applications, and then some other people to write plugins that provided these features, progressively enhanced, based on those interfaces.
It would be a gargantuan effort, though, and you would just end up with a plugin soup without careful moderation (even more effort; and easy to go awry!) so c'est la vie!
And even if it is, rendering text just like Photoshop is just a tiny step towards rendering everything like Photoshop.
I think that Photoshop is an image manipulator first and foremost, and Krita is a tool for drawing/painting, maybe doing some light traditional animation although even that is not it's primary focus.
I think that CSP, Procreate, etc... are more direct competitors to Krita. Photoshop is a competitor to Gimp.
Again, does not change anything about raincole's comment, and I don't think that raincole was suggesting that they were direct competitors. It's just that whenever Photosohp and Krita get mentioned in the same sentence I feel like the assumption from many readers is that they're trying to do the same things, and I would personally say that I think they're separate categories of applications. There are things that Photosohp does that Krita doesn't want to do and will probably never support, because it's a painting app, not an image manipulation app.
Krita: A new brush engine. A new file format for brushes. Some animation features that I don't use. New text system.
PS: AI-based object selection. AI-based neural filter. AI-based generative fill. New Javascript API for plugins.
It's quite clear that Adobe doesn't see PS as a digital painting app, but an (AI-assisted) image manipulation app.
I switched because it seems like it's important to use and support open source tools wherever possible, proprietary software is feeling more and more hostile to the user. I'm redirecting the money I was spending on Adobe products to open source donations.
Don't get me wrong, I love Krita. I used it for years and I wrote ~30+ bug reports. It's a positive thing -- I won't bother reporting bugs to Adobe cause I know they don't care, unlike Krita devs.
However every time I need to collaborate with someone else, they use Photoshop. They use .psd like it's an interchangeable format[1]. Out of 10+ artists I've only seen one who doesn't use PS, and it's not Krita.
[1]: I know Krita can read and write .psd.