Color Under Zimmerit
by Bruce Burden
According the Tom Jentz, red-oxide is the proper color for any areas that weren’t accessible for painting. He contends that the red-oxide was applied at the plant where the plate was cut, then shipped for assembly.
The implication here is that the bottom of a German tank would be red-oxide. None of my books have color pictures any flaked-off areas of zimmerit, but it appears to be a lighter color underneath. Tom Jentz also claims that zimmerit was a good match for dark yellow. What you might see in chipped areas where field-applied zimmerit has chipped off, is the original dark yellow finish below.
If you want to be ambitious, you could have zimmerit, dark yellow paint, panzer grey paint, red-oxide paint and finally some rust in the gouge left by a richochet.