AKRON (Oct. 3)—Most carbon black producers are boosting prices again to offset rising feedstock costs. Degussa-Huls A.G. increased prices of pigment blacks Oct. 1 in Europe. The firm hiked furnace blacks 6 percent and gas and lamp blacks 4 percent. Columbian Chemicals Co. will raise the price of rubber-grade carbon blacks made in North America effective Nov. 1. The increase will add about 7.5 percent to the current cost of the company´s carbon blacks. Furnace carbon black producer Sid Richardson Carbon Co. of Fort Worth, Texas, has not made a decision on price hikes but it is reviewing the situation, a spokesman said. Cancarb Ltd., which soon will be acquired by Sid Richardson, will hike thermal gas prices about 15 percent beginning Nov. 1.