thanks for reaching out!
This is a tough question because the maximum resolution you can export from our software depends mainly on your computer configuration - the more RAM, the better (16 GB is optimal).
Moreover, Rebelle is quite compute-intensive so for larger canvases it would be always better to have a faster processor (i7 preferable) so that the app runs smoothly.
It's because the math running behind is quite complicated, the application itself is different from standard RGBA paint programs, Rebelle has to compute around 25 layers, which include water simulation, diffusion, wetting, drying and all water effects.
This also highly depends on the complexity of the image - the more layers, the more RAM is needed; the more water/wet areas are laid on the canvas, the higher possibility the app can start to lag.
If you purchase the full version, you can test Rebelle on your computer. If the application does not work as you expected, there is always a 30-day money-back guarantee available.
Hope this helps! If you have any other questions, please let us know.