Photographs of corrosion and surface defects
Photographs of flaws in the Allflex films were taken when the boards arrived in September '08 and again in March '09 after being stored in a dry Nitrogen environment. The first two photographs below show that there was already evidence for corrosion or poor quality of the copper surface on one of the 5 micron boards when they arrived from the manufacturer, but it is not clear that this problem became worse over time.
There are marks on one of the 5 micron center boards that from a distance look like fingerprints but actually turn out to be scuff/scratch marks:
Below are before and after photographs for one of the central 2 micron boards. There is evidence for either oxidation of the copper or left-over photo-resist material present upon arrival of the boards from the manufacturer. Again, it does not appear that these flaws got worse over time.