Defect Catalog Extract
Appearance: Diverse in shape, very dark in the area, where the paper is punched. Can be quite large.
Alternative terms: Thin Spot, Water drop
Appearance: Bright area with soft edge, sometimes with periodic occurrence.
Alternative term: Butterfly
Appearance: Two bright areas with soft edges, symmetrically oriented in cross direction.
Appearance: Distinct line across the web.
Appearance: Round or rectangular piece of paper, often with low contrast.
Appearance: Dark and bright area, often lengthwise with a distinct drop-like shape, sometimes with periodic occurrence.
Appearance: Dark area, often lengthwise with a distinct drop-like shape, sometimes with periodic occurrence.
Appearance: Dark spot with variable shape and high contrast. Mostly not periodic. Statistically distributed.
Alternative terms: Dirt, sludge
Appearance: Dark spot with variable, mostly lengthwise shape.
Alternative term: Scrap
Appearance: Dark spot with variable shape and mostly sharp edges. Sometimes blurred, if not in focus of the cameras or on the other side of the web. Can be quite large.
Appearance: Crack, mostly perpendicular to the edge. Often appearing in clusters.
Appearance: Dark with good contrast and sharp edges, up to three layers of paper, often running inwards from the paper edge. Appearance often in clusters.
Appearance: Oriented in machine direction, not always sharp edges, length depending on coating device: up to several hundred meters at a blade coater, usually only a few meters at a sizer.
Appearance: Scratch oriented in machine direction, length can be several hundred meters, usually good contrast.
Appearance: Fine scratch oriented in machine direction, length can be several hundred meters, usually good contrast.