Agreed - LightZone still feels like one of the more intuitive & powerful tools for applying and experimenting with types of filters. It's my preferred tool for

Agreed - LightZone still feels like one of the more intuitive & powerful tools for applying and experimenting with types of filters. It's my preferred tool for doing some quick edits on photos. On a half-way decent machine I find the performance excellent - what kind of slow issues are you finding? Development, if you track the github issues, is down to one guy at the moment. I fear the relicensing of the project was just a smidge too late, and the field was already well populated, for it to attract more interest, unfortunately.