Some plaster used in older homes contains horsehair, which was added to give it greater resistance to cracking. This kind of plaster was implemented in the 1800s and was used in homes up until the 1950s, when drywall became the wall medium of choice because it is sturdier than plaster. So if you have plaster walls in your home and you want to hang a picture, you need to take into consideration that the walls are sensitive.
Things You'll Need
Place a stud finder over the wall to locate an internal stud. Even though the wall is plaster there are still wooden beams behind it which can support paintings.
Mark the area where you found the stud and place duct tape over it. Mark a spot on the duct tape.
Nail a picture hook into the marked area or drill a round-head screw into the mark on the duct tape.
Hang the picture on the screw or picture hook end. The duct tape prevents the horsehair plaster from disintegrating around the screw over time.