Meanwhile, out in the yard...

The prison yard at Eastern State Penitentiary includes several areas along the inside walls where stone or brick and finally plaster or concrete has been used to fill in once open small passages into several of the buildings.  For some reason these fascinated me.  These weren't escape attempts gone bad since they were still within the prison but what was the original purpose of the portals and why were they closed up ?  The prison, located in Philadelphia Pennsylvania, was built in 1829 and closed in 1971.  

Technical details:
Sakai Toyo 5x7" large format metal field camera with 4x5" film back.
150mm Caltar-S II F 5.6 lens in Copal BT shutter.
Ilford Delta 100 film shot at ISO 100.
Exposure was 1/4 second at F22.
Developed in Ilford DD-X 1+4 dilution for 10 minutes @ 20 degrees Celsius using a Beseler 8x10 print drum placed on Unicolor Uniroller 352 auto-reversing rotary base.  
4x5" negative scanned with Epson V600.