This unusual request came from video journalist Brady Haran, who makes videos for the YouTube channel, Numberphile, which shows videos about numbers and math. To celebrate reaching one million subscribers to Numberphile, and in keeping with the mathematical theme of the channel, Brady decided to print Pi to a million decimals. He then wanted to unfurl the reel of paper, totalling more than a mile in length, or 1.7 km, along a runway.
Continuous print of 1,000,000 digits and 1.7 km paper by HSAJET® HP TIJ 2.5
Various challenges had to be overcome before the print run could take place. Project manager, HSA’s UK representative, Hugh McPartlan, initially had to select a print cartridge which would run continuously, then chose the software to enable the number to be printed on a single page length of a mile. Numberphile also wanted the printing to be in the style of the channel i.e. on brown paper. This had to be strong enough to withstand roll out, even in wet and windy weather.
These challenges overcome, the printing was done at HSA Systems in Odense, Denmark, on a vertical reel-to-reel paper transport unit using HSAJET® HP TIJ 2.5 technology. HP Durable Black Ink was selected because of its blackness, clarity, and permanence.
The print system ran at 50 metres a minute, taking about 40 minutes to print the number, which was formatted in 8pt. Courier New font. Alongside the number, the distance in yards was printed and a number count every ten characters.
The next destination for the mile reel of paper was Bruntingthorpe Proving Ground, Leicestershire, where HSA assisted Brady and helpers to unroll the paper. Matt Parker, mathematician and stand-up comedian, talked through some of the significant points of the number during the unfurling of the paper.
Brady Haran said: "It was a crazy request, but the people at HSA were brilliant. They had an answer to every question and a solution to every obstacle. But most importantly, I think we all had fun. Many of the people at HSA are ’Numberphiles’ at heart and it seemed like they enjoyed working with Pi, perhaps the most famous number of all."
Brady and HSA Systems are hoping that they have achieved a world record for the print run, (1851 yards 2 feet 6 ¾ inches), but feel sure they will have got a record at Bruntingthorpe for the slowest time of 4 hours 10 minutes on the track over a mile.