How To Describe Early 1900 Postcard Problem?

I have several early 1900's postcards which were printed in Germany. They have a very slick surface which seems to be a film of some sort. The actual card itself is okay, it's just this film like surface is peeling away.

I was wondering if you could advise me as to what this film like surface is called and how would I describe it to someone who may want this postcard?

Any info or links would be helpful.

The back can give some valuable info, like who printed it and can establish the date.

Reading between the lines, it sounds like you are trying to describe this for ebay. For a description, it would have "rounded and chipped corners with additional edge chipping and overall crackled surface" - or something along those lines. To be honest, birthday cards were produced in immense numbers and so many of them survive, often dumped/found in a 50 cent box at a postcard show (i.e., not worth the postage to ship it today), unless the card is of exceptional quality or design. From what I see, this card is very common and in poor condition.

As for the other side, (the "front" from a postal history standpoint with the view on the back side, but that is for another discussion elsewhere), it could enhance or detract from the retail value if used or from rare/common publisher. We would need an image of it.

I would describe it as flaking varnish.