Charles “Chuck” Geschke, a co-founder of Adobe who helped develop the PDF, has died at age 81, the company said in a statement.

“This is a huge loss for the entire Adobe community and the technology industry, for whom he has been a guide and hero for decades,” Adobe CEO Shantanu Narayen said in an email to Adobe employees.

”As co-founders of Adobe, Chuck and John Warnock developed groundbreaking software that has revolutionized how people create and communicate,” Narayen said. “Chuck instilled a relentless drive for innovation in the company, resulting in some of the most transformative software inventions, including the ubiquitous PDF, Acrobat, Illustrator, Premiere Pro and Photoshop.”

Geschke earned a doctorate from Carnegie Mellon University in Pittsburgh, and then took a job at Xerox Palo Alto Research Center where he met Warnock. The pair left Xerox in 1982 and founded Adobe. Their first product was Adobe PostScript, the programming language that helped boost the desktop publishing industry.

Geschke was chief operating officer of Adobe from December 1986 to July 1994 and president from April 1989 until his retirement in April 2000. He served as chairman of the board with Warnock from September 1997 to January 2017 and was a member of the board until April 2020, when became emeritus board member.

“I could never have imagined having a better, more likable, or more capable business partner,” Warnock said in a statement. “Not having Chuck in our lives will leave a huge hole and those who knew him will all agree.”

In addition to his contributions to the technology industry, Geschke was also known for surviving a 1992 kidnapping attempt. Two men snatched him as he arrived at work one morning and held him for four days, demanding ransom. He was eventually rescued by the FBI.

President Obama awarded Warnock and Geschke the National Medal of Technology in 2009.

“He was a famous businessman, the founder of a major company in the U.S. and the world, and of course he was very, very proud of that and it was huge achievement in his life, but it wasn’t his focus — really, his family was,” his wife Nancy Geschke, 78, told the Mercury News. “He always called himself the luckiest man in the world.”

Geschke is survived by his wife Nancy, who he was married to for 56 years, three children and seven grandchildren.