Universal and special indicator papers pH indicator papers have been on the market for decades and are the standard for many applications. For each pH-value these papers show a single color which can be matched with the color scale at intervals of 0.2 –1 pH. The characteristic features of pH indicator papers are: pH indicators are supplied in plastic reels that ensure long term stability and protection against many external influences. The indicator paper will always be ready-to-use when needed. pH indicators are manufactured from high quality filter papers from MACHEREY-NAGEL. Combined with our ISO 9001 quality control scheme this ensures optimal quality. The user will always get reliable readings. The colors of the color scales are specially mixed to perfectly match the reaction color of the indicator papers. This makes the read-off of results easy and accurate.