I've just been stripping the wallpaper in the third bedroom in my 1930 bric k-built semi.
I was interested to find that when it was plastered they created a very nea t strip of dark grey plaster about half a metre wide down from the ceiling and the rest of the wall was done in much lighter plaster.
There's a very neat joint between the two.
This was probably the height of fashion in 1930 and there's evidence of som e kind of paint pattern on it in some places - I've never come across anyth ing like this before - but most of my previous experience of stripping wal ls has been in houses built in about 1880!