Hopefully you will get more answers. First thing I would do with what you have already printed is determine if the print is actually 830 mm wide.
Then if an inkjet printer does it impose a 'feed' margin at the end of the print. Is the printer scaling the image 'to-fit'. All unknowns here.
I once had a Canon inkjet that would not print panoramas. Got up to 40 cm on roll paper and stopped there Truncated the image.
Then if an inkjet printer does it impose a 'feed' margin at the end of the print. Is the printer scaling the image 'to-fit'. All unknowns here.
I once had a Canon inkjet that would not print panoramas. Got up to 40 cm on roll paper and stopped there Truncated the image.