Nobody could claim you for copyrights as they become over in 50/70 years after the deceased of the author
So, in no case prints from 1780-1880 could be under copyright sistem protection
In all cases be carefull not to copy the real sign of the author because it could be considerer falsification Usa alwyas your own sign
I will be here if needed
I hope you could reach the link right now.
Moderators tell me that you could not