Ask HN: Where to go from here for more image processing?

I started in photography in 1991 in a third world country. I have been a professional photographer since then. Eventually found myself in an European country. Tried a lot of different paths along the way, considered myself as an artist most of this time. But digital imaging professionally kept me fed. Investigated into programming for a long time. Joined the Processing madness when it first came out, Arduino too, etc. Passed on many opportunities to work in image processing, didn't think it would be so much fun. Have always been an experimental photographer, for sure.

Many years later I was at a job (my last one, as an e-commerce photographer) that gave access to a learning platform. During one low season, I decided to refresh and expand my programming skills and soon enough I was able to get things done in a way I never thought possible, specially after so long.

A lay-off was in my path this time and it was most welcome. Time to think and plan my next steps, it has been great, seriously. I have been using this time to write simple apps. Recently I finished a trio of apps that reflect the experimental photography I have been doing all these years. One deals with mixing color channels, one creates slit scans from videos (which was the hype when Processing came out) and the last one with solarization of images. All things that I practiced first-hand in the analog world or the digital experimental world. It has been really interesting to learn the math of the images.

With these initial apps under my belt, I'm eager to delve deeper into image processing. Any suggestions for inspiring resources or projects?