Hey Bruce, here are some pictures to look at. The first is the one I go off of since it is the most clear picture followed by another picture of the same aircraft and how the image quality make it look different, and then some other examples.
Clear pic showing a hard line.
This one not as good a quality but just enough to show a hard line but it does look like a softer line.
The aircraft I am doing:
This I think was actually the original picture but the previous one had color added (I think)
Is is a hard or soft line? Unless you are trying to be 100% accurate (which you truly will never be) just go with looks right to you. This can be done as a softer line and justified by the colorized picture or done as a hard line and justified by a similar aircraft with a phot with much more detail. Reality is we don’t really know unless you happen to talk to the pilot who flew it and he can say what it was. I think another factor plays in and that these 109s didn’t stay clean and where not polished up. Wear and tear on the paint due to dust and dirt played a factor, though not like a Zeke on a coral island with the low quality paint that fell off just looking at it.