Thank you, Mike. GigaPan does not require TIFF. It's just that I need a file format that allows me to go between PS and PI.
Rob, That's a good idea. Thank you. This will allow me to go to effectively 12 GB. I was originally thinking about cut a large image into multiple pieces and then process them separately. This won't be ideal for ABE/DBE. But splitting the image into three channels should be OK. Ultimately, I would hope I won't be limited to 12 GB. But for now, it should be sufficient.
Gerald and Niall, I believe pretty much everything people do in PS can be done in PI. It's just that I have used PS for more than 20 years. I have a much longer history with PS and I am so used to its tool and interface. Switching from PS to PI completely will hurt my productivity a lot. So I do not consider it an option. When I go from the 32 bit stacked image in PI to 16 bit TIFF for PS, I took some precaution. So far, I see no evidence that my results are limited by the 16 bit resolution.
Cheers,
Wei-Hao