Test Media Systems

Classification of test media
A combination of penetrant, remover and develolper is reffered to as a test media system for penetrant testing. The following types are distinguished:

Penetrant
I: Fluorescent Penetrant Testing
II: Colour Contrast Penetrant Testing
III: Fluorescent Colour Contrast Penetrant Testing

Remover
A: Water
B: Lipophilic Emulsifier
C: Solvents
D: Hydrophilic Emulsifier
E: Water and Solvents

Developer
a: Dry Developer
b: Wet Developer on water basis, water soluble
c: Wet Developer on water basis, suspended
d: Wet Developer on solvent basis
e: Wet Developer on water or solvent basis
(for special application)

Colour contrast or fluorescent penetrant
Fluorescent penetrants are preferably used for static series testing. If testing takes place in daylight conditions, colour contrast penetrants offer advantages. For the use at randomly changing locations, penetrants are also offered as spray cans. In any case you have to take care for the different sensitivity of the systems.

Selection of remover
Water is used for most PT purposes as penetrant remover. For special requirements emulsifiers can be used, e.g. for higher sensitivities.

Developer Systems
Geometry and the amount of pieces to be tested are factors for the type of developer to be used. For colour contrast penetrant testing, quick drying wet developer based on solvents are commonly used. For series testing with fluorescent penetrants dry developer or water suspendable wet developers are more convenient.

Delivery form
Penetrants are offered generally as ready to use product for application security. Eliminating errors of wrong mixture concentrations, which would have an important effect to the system sensitivity. Wet developers are mostly offered as concentrate for dilution.