We’re already past those days where non-destructive photo-editing is exclusive to Adobe Photoshop. Paint Shop Pro probably has it. But, certainly Photoflow, Affinity Photo, Krita does. And non-destructive editing always applies changes. No need to flatten to see changes.
Non-destructive editing is not exclusive to having adjustment layers. You can have adjustment mask ala smart filters in Photoshop, or adjustment mask in the form of Affinity Photo or Krita. There’s file layers, transform masks, and clone layers. All of those are essentially things that are non-destructive. Also, non-destructive layer effects counts too.
I have been following this back and forth and I can assure you that this kind of debate can be found everywhere on the web. What I would say is that builtin non-destructive editing is quite convenient and keeps the layer, mask, etc., stack more manageable, especially when you are working upwards of 10 layers. Sure, you could group, duplicate, delete and move items; but I am not that agile.
It also helps simplify tutorials. Try following @Elle’s GIMP tutorials; not everyone can follow due to the sheer amount of steps involved.
In the end, it is just another paradigm. Like I said in other threads: someone claims app or method A is better than B and that app B should adopt features from A. It might be superior or it might not be, but to fight over it isn’t necessarily the best approach to make friends and motivate devs.
For my part, I only recently began to experiment with using GIMP. As someone who does astronomical (and planetary) image processing, the availability of adjustment layers à la Adobe Photoshop is indispensable. On that basis I could not recommend GIMP as a program solution to anyone doing similar work.
Then in that case, your options is Krita and Photoflow, and RAW processing software. Krita while generally viewed as a painting software do have adjustment layers/masks, and some generic editing tools including G’MIC support as well as LAB color space support. Photoflow is much more for photographic editing than graphic design.
Recently Gimp has received a 100.000 $ donations, let’s hope non destructive editing will be one of the next features
I can obviously use Gimp as it is, but i think it is one of the features i miss most (the other ones being a way to easily and graphically record a macro and a native lensfun plugin)
With respect to astronomical image processing there are a number of specialized image processing applications available, both free and paid. For Photoshop, ESA/ESO/NASA (European Space Agency/European Southern Observatory) created the FITS Liberator plugin so that Photoshop would be able to read FITS (Flexible Image Transport System) files - which is the standard format for astronomical imaging. The plugin also does some basic image processing.
With all due respect, I should let you know that I do not specialize on astronomical image processing. So, I can only give options based on fields related to graphic design industries and knowledge of alternatives to Photoshop for certain needs.
