I may have discovered the problem. In order to get an 800MB image in the 10 inch x 360 inch range, I have to go higher than 65,536 pixels on the long edge. QU is currently (always has been) limited to 65,536 pixels in either direction and that may be the problem. It should give you an "Image Read Error" instead of the mentioned error message but it shouldn't matter in the future. The QU 20th Anniversary Edition releasing later this summer will have the capability to do twice that pixel size.
Regards,
Mike
Mike, the odd thing is that Bernard etc finally decided to bundle 3 of the files in one image, total 2.5 GB, 8 bit, 280 PPI, >72x960 cm print area, and print from Photoshop on the iPF Pro 4000, with your size creation of the 4000 driver in mind. He phoned me at 75% of the length printed, fingers crossed, and the print was ready some hours ago. Now he has to fold the leporellos and cut them while folded .........
I guess further back in time they never hit that length in pixels (lower resolution files), though they reduced the resolution for the trials this time to get this job done and it failed with QU. Might still be another cause given the error text.
My jobs did not go beyond 5 meter if I recall it correctly. I used Qimage's print to file then to first set multiple images after another for a 5m long leporello image. Three of the files then on the print page, some white extra for tolerance at both ends, 1mm white +border and dashed lines along the length for cutting by hand later on. Folded after cutting, cut the extra white at the ends then. Worked well. Not my favorite jobs.
Met vriendelijke groet, Ernst
http://www.pigment-print.com/spectralplots/spectrumviz_1.htmMarch 2017 update, 750+ inkjet media white spectral plots