Rendering screen twice

Hi everyone!

For some time i’ve been trying to solve a problem with rendering same screen twice with and without post process to save it as a file for later.

Now im just making a screenshot, stopping time, adding postprocess waiting single frame and saving screen as another screenshot.

I’m wondering if its possible to process already rendered data again but with a different postprocess material and save it to disk. It sounds managable but rendering pipeline is something completely new to me and i dont know how to even start.

Any suggestions?