Personal belongings were taken upon arrival to a section of the camp referred to as “Canada”. Called “Canada” because people brought valuables (thinking they’d use at their relocation) and the Americas were viewed as prosperous. The Germans took anything of value, burned anything personal. These “Canada Warehouses” were subsequently destroyed by the Germans (along with gas and cremation facilities) to hide evidence of wrongdoing.
Correction, upon arrival they were allowed to keep one item…a belt…because they’d lose weight quickly.
I think guide said initially they’d photograph each inmate, but as cost of film and developing increased, they began using tattoos to save money. Also, as the death toll grew, tattoos were an easier way to identify the bodies.
Each prison uniform had a distinguishable patch so guards could quickly identify the category of prisoner. IE – political prisoners had a red triangle, criminals a green triangle, Jews a yellow star of David, Jehovah witnesses purple triangle, etc.
See bunk pic below, 5-6 people slept on each level.