Essen 160 Strips 1-14 Test Paper PH Indicator Alkaline Acid Water Litmus Testing Kit Other
£4.54
Acidic or alkaline? Now you can distinguish between what paper or board is suitable for conservation with the stroke of a pen. The solution will turn a shade of purple on paper with a pH of 6.5 or higher. Any other color would indicate a pH lower than 6.5, thereby acidic and unsuitable for artwork that is meant to last.