I'm going out on a limb and guessing you've never written an application of any complexity that required it's own binary file format. I don't mean that as a sl

I'm going out on a limb and guessing you've never written an application of any complexity that required it's own binary file format. I don't mean that as a slag, but your comments leads me to believe that is the case and, therefore, your understanding of the issue is purely speculative. I also think you missed the point, PSD is not designed to be an interchangeable format nor a public one. It is designed to operate specifically with it's origin application, therefore why should Adobe care if third party developers have a hard time implementing it? That's not their problem. There is no onus on Adobe to create some magic file format that third party developers can easily implement. What is their problem is a performant file format with backwards and forwards compatibility that must store a lot of application specific stuff. Stuff that only their application needs to deal with. As someone who has written a PSD importer for Delphi (in Pascal!) using Adobe's docs, it's really not that terribly difficult for most use cases. It's just as clear as working with any other RIFF-esque file format. You can write a simple importer in a couple of days, and a more in-depth one within a week. ymmv, ianal.