Cobalt Chloride impregnated blotter divided into nine sections which exhibits various colours from blue through lavender to pink.
The position of the lavender section indicates the relative humidity of the surrounding air.
Humidity indicator cards can be used with ESCAL® and PTS® bags as a long term check against punctures and ingress of moisture.
Escal and PTS films are barriers to moisture so fluctuations in moisture will indicate the enclosure is leaking.
Archipress™ and CXD low barrier pouches offer good protection against oxygen, but moisture molecules being much smaller can pass through the plastic layers therefore humidity indicators are not relevant for those films.