Spots on the part are not taking the metal finish. There are a few things that can cause this problem. The most common is that the part needs to be sufficiently wetted. You may have noticed the water breaking when spraying SR solutions on the part. On larger parts, you may need to repeat steps 3 and 4 several times. The next factor is the age of the D solution. This chemical has a shelf life of six months. The last factor is surface contamination. This can be obvious in the form of visible nubs in the base coat or less evident in the form of fingerprints, latex residue, or overspray from other projects.