The Fair Trade Commission warned the Photo-sensitized Materials Manufacturers Association on Friday against hindering fair competition in the domestic market by exchanging trade information detailing production, shipments and shipping prices of their products among member companies.

According to commission officials, the association, consisting of four major domestic makers, has collected monthly trade information on film and negatives from its members since 1978 and distributed it exclusively to the member companies.

Although the commission failed to prove that the association has hindered competition through the acts, the information may have helped member companies form tacit agreements concerning restrictions on production and shipments, commission officials said.

Such a warning targeting only dissemination of data is unprecedented, the officials said, adding that the commission has taken into consideration the huge scale and highly oligopolistic state of the market.

Of the four association members, Fuji Photo Film Co., Konica Corp., and Mitsubishi Paper Mills Ltd., accounted for 79 percent of film shipments and 71.7 percent of negative shipments in 1994, according to the commission. The fourth member is Oriental Photo Engineering Co.