Fife-based paper maker Tullis Russell has gone into administration with the loss of 325 jobs, and putting a further 149 at risk.
The company has seen European exports suffer from the value of sterling in relation to the euro.
It has also been hit by rising raw material costs and by a major customer becoming insolvent.
Administrators KPMG said 325 Tullis employees were being made redundant with immediate effect, while the remaining 149 have been retained to complete some orders.
Employee-owned Tullis was founded in 1809 and produced high quality paper board for use in cards, covers and premium packaging.
The paper maker has incurred cumulative losses of £18.5m over the last five years, largely as a result of weakening demand and pressure on its margins.
Tullis directors had sought a buyer for the company last autumn, but failed to find one.
Joint administrator Blair Nimmo said: "This is a sad day for the employees of Tullis Russell Papermakers, who have worked hard against the significant headwinds facing the global papermaking sector.
"Whilst we will be exploring whether a sale of all or part of the business and asset of the company can be achieved, we have had to take steps to significantly reduce the company's overheads.
"Unfortunately, with trading effectively ceasing, we have had no option but to reduce the size of the workforce.
"We will be working with government agencies to minimise the impact on employees.
"We would encourage any party with an interest in acquiring all, or parts, of the business to make contact with us as soon as possible."
Tullis Russell Papermakers is a wholly-owned subsidiary of Tullis Russell Group Ltd.
The group's Cheshire-based coating division and its image transfer business based in Ansan, Korea, are not affected by the administration and continue to trade as normal.
Tullis Russell Group said it was announcing the administration move "with great sadness".
Group chief executive Chris Parr said: "It has become clear to the board that Papermakers is no longer a viable business.
"Recognising this situation, the group and Papermaking boards concluded that the best chance of protecting jobs would be through a trade sale of the papermaking company to a buyer capable of, and committed to developing the Markinch site.
"The group engaged KPMG to run a comprehensive sales process, and between October 2014 and March 2015 over 72 trade parties have considered and subsequently rejected the opportunity to acquire the business. This has unfortunately only confirmed that the business is no longer viable.
"This difficult position finally became untenable with the papermaking company's third largest and most profitable customer entering into an insolvency process on Monday 1 April 2015.
"The directors of our Papermaking business were therefore faced with no other option than to place the business into administration.'