The ProcessTwo test procedures have been developed by a DIN work group and published in the DIN 75201 standard for determining the amount of undesired evaporation. These are generally called procedures "A" and "B". The DIN work group has hereby defined a working procedure and a set of test conditions governing the usage of testing instruments used for foggingtest so as to enable a certain comparability of the measuring results. This DIN standard was adopted to the ISO 6452/2000 standard so that the following description of the method is valid for both standards.

Fogging behavior DIN 75201-R Process "A": Determination of the fogging behavior by measuring the reflectometer value (R). According to this procedure, a material sample is temperature controlled at 100C for 3 hours. The volatile components condense on a glass plate cooled to 21C. In this way the evaporation process which normally takes place in motor vehicles over a longer period of time as a result of the interior being heated up by the sun’s rays is simulated in "quick-motion". The amount of fogging condensation on the glass plate is then qualitatively recorded by measuring the 60 reflection value. A 60 reflection value of the same glass plate without condensation serves as a reference.

Fogging behavior DIN 75201-G Process "B" (gravimetric method): Determining the fogging behavior by weighing the condensed component (G). As opposed to process "A", a sample placed in a beaker is temperature controlled at 100C for 16 hours. The beaker is covered with aluminum foil which has been previously weighed. The amount of fogging condensation is determined by weighing the foil again after the test.