Otto Kumm signature authentic?

[Justin Holmes]

Hi all,
This looks like a good post-war signature compared to others but would like your opinions.

Unfortunately it's glued down to felt in a small display so I'm not sure if a postcard or a copy photo.

Thanks in advance, Justin

Sent from my SM-G955U using Tapatalk

[markus]

For me 100% original and I hung out with Otto a couple of times at his home where he signed photos and books for me...

Markus

[Justin Holmes]

Thanks Markus! Much appreciated.

Sent from my SM-G955U using Tapatalk

[max history]

It looks original, but avoid modern glued photos. The glue eventually seeps through the photo paper and stains the photo badly with discolouration. It is more likely to happen with modern photo paper than old paper - probably something to do with acid content.
Max.