ISO 6588:1981

Paper, board and pulps — Determination of pH of aqueous extracts

Is applicable to all kinds of paper, board and pulps yielding an extract having a conductivity exceeding 0.2 mS/m when determined in accordance with ISO 6587, except for papers used for electrical purposes. For high purity papers used for electrical purposes, the method should be that given in IEC Publication 554-2.