Hello Clever peeps

I have been away for some time, merrily trying to restore what is now 3 boxes of family photo's.

This one is really giving me some problems, it is on some sort of heavy 'stuff' comes out a bit like glass, and as you see very very dark - it can be lightened, but the faces are so bad every time I try I disfigure the family

The lady at the back of the car is my nana, next to her is g grandma and the young man is a great uncle. I only know its my nan by the shape of face and hair, so each time I try restore it I loose that

Anyone fancy a challenge?
Lynda