The Amendment 1 to IPC-4556 made the following changes to the base specification: a) It added the absolute value of the maximum thickness for the immersion gold of 0.070 μm [2.8 μin] that accompanies the statistically valid minimum immersion gold thickness; b) It added two more photomicrograph images to provide better information on identifying nickel hyper corrosion; c) It added the basis of determining both the minimum as well as maximum values of immersion gold thickness with ENEPIG surface finish; d) It added the statement that using statistical process control is encouraged but not mandatory with this surface finish; e) It provided two alternate methods for deposition of thicker gold compared to strictly immersion gold; and f) It better defines how the C=0 sampling plan is to be utilized such that it will conform to this surface finishes' requirements.