Dear Maintainer, The dimensions of pages given by pdftk's "dump_data" command include separator commas for sizes 1000pt or greater. When such output is read back in by the "update_info" command, large widths generate a warning. But for large heights, the commas are interpreted as decimal points, causing the pages to become drastically resized. It is possible that this is locale-dependent. My locale has LC_NUMERIC="en_GB.UTF-8" . Here is an example of the problem for a tall PDF: $ pdftk tall.pdf dump_data output tall.txt $ cat tall.txt InfoBegin InfoKey: CreationDate InfoValue: D:20251121050436Z InfoBegin InfoKey: Producer InfoValue: cairo 1.16.0 (https://cairographics.org) NumberOfPages: 3 PageMediaBegin PageMediaNumber: 1 PageMediaRotation: 0 PageMediaRect: 0 0 264 1,099.92 PageMediaDimensions: 264 1,099.92 PageMediaBegin PageMediaNumber: 2 PageMediaRotation: 0 PageMediaRect: 0 0 264 1,099.92 PageMediaDimensions: 264 1,099.92 PageMediaBegin PageMediaNumber: 3 PageMediaRotation: 0 PageMediaRect: 0 0 264 1,099.92 PageMediaDimensions: 264 1,099.92 $ pdftk tall.pdf update_info tall.txt output tall2.pdf $ pdftk tall2.pdf dump_data output tall2.txt $ cat tall2.txt InfoBegin InfoKey: CreationDate InfoValue: D:20251121050436Z InfoBegin InfoKey: Producer InfoValue: cairo 1.16.0 (https://cairographics.org) NumberOfPages: 3 PageMediaBegin PageMediaNumber: 1 PageMediaRotation: 0 PageMediaRect: 0 0 264 1 PageMediaDimensions: 264 1 PageMediaBegin PageMediaNumber: 2 PageMediaRotation: 0 PageMediaRect: 0 0 264 1 PageMediaDimensions: 264 1 PageMediaBegin PageMediaNumber: 3 PageMediaRotation: 0 PageMediaRect: 0 0 264 1 PageMediaDimensions: 264 1 Compare the results for a wide PDF: $ pdftk wide.pdf dump_data output wide.txt $ cat wide.txt InfoBegin InfoKey: CreationDate InfoValue: D:20251121050527Z InfoBegin InfoKey: Producer InfoValue: cairo 1.16.0 (https://cairographics.org) NumberOfPages: 1 PageMediaBegin PageMediaNumber: 1 PageMediaRotation: 0 PageMediaRect: 0 0 1,098.96 264 PageMediaDimensions: 1,098.96 264 $ pdftk wide.pdf update_info wide.txt output wide2.pdf pdftk Warning: unexpected PageMedia case in LoadDataFile(); continuing $ pdftk wide2.pdf dump_data output wide2.txt $ cat wide2.txt InfoBegin InfoKey: CreationDate InfoValue: D:20251121050527Z InfoBegin InfoKey: Producer InfoValue: cairo 1.16.0 (https://cairographics.org) NumberOfPages: 1 PageMediaBegin PageMediaNumber: 1 PageMediaRotation: 0 PageMediaRect: 0 0 1,098.96 264 PageMediaDimensions: 1,098.96 264