Strip a wall in an old house and you rarely find one wallpaper. You find a compressed stack of them, each layer a decision somebody made about how the room should look, pasted straight over the last.
Read carefully, that stack is a rough chronology. It will not give you exact dates, and anyone who claims otherwise is guessing, but it narrows things considerably.
Start with the paper, not the pattern
The substrate is more diagnostic than the design. Early papers were printed on small handmade sheets joined into lengths, and the joins are visible as faint horizontal lines at regular intervals. Continuous machine-made paper replaced this during the nineteenth century, so a paper with no join lines is generally later.
Thickness, texture and the colour of the reverse all help. Very white, smooth, even backing is modern.
Look at how the colour sits
Hand block printing leaves colour sitting on the surface, slightly raised, with tiny registration errors where one block did not quite meet the next. Those small misalignments are the clearest sign of block printing, and they are worth looking for with a glass.
Machine roller printing is flatter, thinner and almost perfectly registered. Later still, you find printed dot screens, which place a paper firmly in the modern period.
Pattern tells you about the room
Design moves in broad waves, and while any motif can be revived, the combination of scale and placement is informative. Large repeating patterns in strong colour tend to belong to periods when walls were divided horizontally. Smaller, sparser, paler patterns often indicate a later scheme in the same room, when the dado had gone and the wall was treated as one surface.
Where a dark paper stops partway up and a different paper begins, you are looking at the outline of a dado that no longer exists.
Handle it properly
- Photograph the layers in place, with a ruler alongside, before removing anything.
- Take a sample from an inconspicuous corner rather than the middle of a wall.
- Keep fragments flat and dry between acid-free sheets, never taped.
- Note which room and which wall on the outside of the envelope. This is the piece of information everybody forgets and nobody can reconstruct.
What it is really for
Dating is the lesser part of it. The more interesting thing is the sequence, the evidence of a room being redecorated every fifteen or twenty years by people who each thought they were improving it.
Whatever is on the wall now is simply the current layer, and it will be somebody else’s archaeology.