UPM Shotton celebrated its 20th anniversary last month with reunions of past and current staff.
Both groups were invited to an exhibition looking at old uniforms, company memorabilia and photographs.
UPM Shotton head of fibre purchasing Martin Green said: "It is such a fantastic feeling to look back at the last 20 years and to see how much of a difference the company and the workers have made to changing people's perceptions about recycling.
"Without the recycling efforts of thousands of people in the UK, this plant simply wouldn't be able to function. Everyone that participates in their local authority recycling scheme is part of this fantastic success story."
When it was first opened, it made newsprint from renewable forests. It then moved to a blend of 65% recycled fibre and 35% virgin fibre from UK renewable forests. Then in 2003, it completed a conversion to 100% recycled fibre and boosted the UK's total paper recycling capacity by 30%.