Which factor does NOT impact the resolution of an eddy current testing system?

The resolution of an eddy current testing system is influenced by several factors, which include the frequency of the test signal, the geometry of the specimen, and the conductivity of the material being tested. These elements directly affect the electromagnetic fields and the interaction between the coils and the specimen, which are crucial for detecting flaws or material properties.

The frequency of the test signal plays a vital role in defining the depth of penetration of the eddy currents into the material and thus affects the system's ability to detect shallow versus deep defects. Similarly, the geometry of the test specimen can alter the paths that eddy currents take, impacting the system's resolution. Material conductivity is also a key factor, as it determines the effectiveness of eddy current generation and, hence, the detection capabilities.

In contrast, the color of the test specimen does not have any bearing on the resolution of an eddy current testing system. While color might influence visual inspections or non-destructive testing methods that rely on visual cues, it does not affect how eddy currents are generated or how they interact with material properties. Therefore, this factor is not relevant in the context of resolution in eddy current testing.