Vintage35
Established
I got my 1939 Summar in the mail today and it had what the seller was calling "cleaning marks". I noticed it looked just as my former 1936 Summar with this crusty edge looking.
I looked at it with a loupe and sure enough it was raised and not just scratches. a small test with my fingernail started scraping some off so I knew it wasn't just cleaning marks.
here is my former 1936 Summar, the gunk seen without back-light. This seems to be common:
I used the same method for cleaning fungus, 50/50 household ammonia and hydrogen peroxide. the edges started foaming and after letting it sit a minute or two, wiped it clean and finished with a wash of plain water.
after looking at it with a flashlight from behind, I had to do a second cleaning in the middle area and basically the entire lens surface rather than concentrating on the edges.
it now looks a lot better and not as hazy as before. I wish I had done this to my first Summar as it was a matching 1936 with my 1936 IIIa.
I looked at it with a loupe and sure enough it was raised and not just scratches. a small test with my fingernail started scraping some off so I knew it wasn't just cleaning marks.
here is my former 1936 Summar, the gunk seen without back-light. This seems to be common:
I used the same method for cleaning fungus, 50/50 household ammonia and hydrogen peroxide. the edges started foaming and after letting it sit a minute or two, wiped it clean and finished with a wash of plain water.
after looking at it with a flashlight from behind, I had to do a second cleaning in the middle area and basically the entire lens surface rather than concentrating on the edges.
it now looks a lot better and not as hazy as before. I wish I had done this to my first Summar as it was a matching 1936 with my 1936 IIIa.
Good work! The front element looks very decent now. I had a Summar with similar gunk as well, but it was also scratched up quite a bit and had internal haze so didn't clean up anywhere near as well as your lens. Would be interesting to know what the gunk actually is.