Bob, I have always considered them to be absolute. If relative - relative to what? Do the cardboard indicators provide a temp range for which they are valid? Steve C -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Robert Kondner Sent: Friday, March 08, 2013 11:24 AM To: [log in to unmask] Subject: [TN] Humidity Measurements: Relative or Absolute Hi, As I start looking at humidity measurement devices I started to wonder if IPC humidity numbers are Relative or Absolute? Does anyone know off hand. I need to go buy some specs. I would have thought Absolute but the cardboard indicators are temperature sensitive as are the desiccant drying systems in dry cabinets. If the temperature is high, say > 100C then a part will "Bake Out" regardless of the absolut humidity, is that right? Bob K. ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________