Since the photo paper consisted of a carrier paper and a picture layer made of gelatine with embedded silver salts until around 1960 , the gelatine layer in old photos can swell up again due to moisture (in damp apartments without sufficient air exchange ). This can cause photos on opposite sides of a photo album to stick together. The thin interlayer paper protects against this. Its spider embossing prevents at least full-surface sticking. Alternatively, glassine interleaves are also available with linen embossing .
Modern photos have an image layer with plastic film that cannot swell. That is why spider paper is no longer necessary today.
- Hans-Jürgen Lorenz, Hans G. Möntmann, Herbert Kuhn (Association of German Paper Mills): Of course paper: a material with a future - 600 years of paper in Germany, 1390-1990 . Edition Braus, 1990, ISBN 978-3-925835-91-9 , p. 130.