It is not for printing it is to make a very high definition file of a painting displaid on the web with KRPano. I need a jpg file or a tiff file to create the tiles. And photoshop also do not save tiff files larger than 4 Gb...
Ah, but since KRpano will make smaller tiles out of the image, is it not possible to split the file, e.g. in 4 large tiles to begin with, and add the subdivisions below that. I haven't looked at the KRPano segmented output, but assume there is some documentation about such huge files to assist. Are you sure it can't import PSB files?
I use
Pano2VR for such work, and that allows PSB files as input, before subdividing into multiresolution JPEGs for HTML5 or Flash/SWF output.
Cheers,
Bart