• Printing&Writing
  • Printing&Writing
  • 印刷和书写


Defect Catalog Extract


Alternative terms: Sludge, slime hole, Pinhole

Appearance: Diverse in shape, sometimes with a dark area, where the paper is folded. Circular in shape and very small.

Bright Spot

Alternative terms: Thin Spot, Water drop

Appearance: Bright area with soft edge, sometimes with periodic occurrence, often lengthwise.


Dark Spot

Alternative terms: Dirt, sludge, Scrap, debris

Appearance: Small dark spot with variable shape and high contrast. Statistically distributed. Sometimes in bursts across the whole web; can be quite large.

Edge Crack

Appearance: Crack, sometimes combined with a wrinkle mostly ending at the edge. The wrinkle is often sickle-shaped.



Appearance: Dark with good contrast and sharp edges, up to three layers of paper, often running inwards from the paper edge.


Appearance: Oriented in machine direction, not always sharp edges, length depending on coating device. Width may vary considerably.




Pascalstraße 16
52076 Aachen
tel: +49 (2408) 92 700 - 0
fax: +49 (2408) 92 700 - 500

Supported Applications

  • Coated but offline / WIS at base paper
  • Coated (WIS at coated paper)
  • Light weight coated
  • Fine paper uncoated

Customer Examples

  • APP
  • Leipa
  • MD Papier
  • Norske Skog
  • Perlen Papier
  • Sappi
  • SCA
  • Shandong Chenming
  • Stora Enso
  • UPM-Kymmene