1. Paper technology
Paper properties
1 Technical Support Sappi Fine paper Europe
| Paper properties | Sappi Fine Paper Europe

2. Colour space
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3. Measuring methods
Colour space Lambda-Spectral area
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4. Measuring methods
Gloss Roughness
Brightness
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5. Conversion
Rate of factor THICKNESS BULK :
Thickness (mm)
BULK (cm3/g) = x 1000
Basiswight (gsm)
Rate of factor BULK THICKNESS :
Bulk (cm³/g) x Basiswight (gsm)
THICKNESS (mm) =
100
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6. Formulas
Start of the Excel-file with double-klick !
For your input please use the grey fields only !
When you will have the number of sheets no data in the grey field !
Length (cm ) Weight of the pallet (kg) 0,0
Width (cm ) Height of the pallet (cm ) 0,0
Num ber of sheets Num ber of sheets #DIV/0!
Dicke (µm ) Bulk #DIV/0!
Gram m age (g/m ²)
Weight of the pallet (kg)
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7. Machine direction
1000 x 700 mm Machine direction
Wide web
700 x 1000 mm
Small web
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8. Machine direction
1. The nail test. 2. The strip test.
Pressure with the Two strips with the
finger nail over both same length and width
edges creating a are cut out off the length
differently strong and width of the sheet. If
corrugation formation. these strips are hold
horizontally, the
deflection of the strip is
stronger in crosswise
direction.
3. The humidity test 4. The tearing test.
A piece of paper is taken By tearing down the
off the sample sheet and sheet in longitudinal
moistened on one side. and crosswise
The rolling-in, caused by direction the machine
the humidity expansion, direction can be
indicates the machine learned from the
direction. tearing edges.
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9. Machine direction
1. The more wavy side is located 2. The more rigid strip is lying in machine direction
crosswise to the machine direction.
3. The sides with the edges coming to the 4. The smoother tear is parallel to the
top are in machine direction. machine direction.
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10. Humidity of paper
 Relative Humidity
= Air humidity between sheets and between
paper windings of a reel
 Absolute humidity
= % humidity in the paper
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11. Temperature °C Relative air humidity (RLF) in %
10 64 73 82 94
12 55 65 73 82 92 98
14 49 59 65 73 82 87 97
16 43 55 57 65 78 87 93 97
18 38 45 50 57 64 70 75 83 85 95
20 34 40 45 50 56 62 67 73 76 84
22 30 35 40 45 50 55 60 65 70 75
24 27 32 35 40 45 50 54 67 62 68
26 25 28 32 37 40 45 47 53 55 60
28 22 26 28 32 36 42 43 46 50 55
30 20 23 26 29 33 38 39 43 45 50
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12. Recommended time for the acclimatisation of
pallets in hours
Paper quantity
per pallet Temperature difference of the paper Storage room
5 °C 7 °C 10 °C 15 °C 20 °C 25 °C 30 °C 35 °C
approx. 0.2 m3 4 7 9 15 21 28 41 62
approx. 0.4 m3 7 12 17 26 36 41 64 92
approx. 0.6 m3 9 15 20 31 42 55 76 107
approx. 1 m3 12 18 23 33 46 63 84 115
approx. 2 m3 13 19 24 35 49 66 90 123
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13. Flat position
Wavy-edging
Baggy
middling
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14. Classification of papers coated on both sides for the sheet
and web offset printing
• Originally coated art papers
Coated papers of highest quality for a high demand. Very high coating of
very high uniformity and elegance. Best printability and processability.
• Specially coated picture printing papers
Coated papers for demanding and high quality printing jobs with a high
quality constancy and reliability. Very economic printability and
processability.
• Standard picture printing papers
Coated papers for the daily need for which standard quality is sufficient.
Numerous manufacturers of such papers produce different qualities.
• Consumer picture printing papers
Coated papers for simple printing jobs for which not the highest quality
regarding gloss and uniformity of the printing picture is required.
The coating is carried out within a paper machine or offline, this means separately on a
coating machine. The coating quantity mounts to 5 – 30 g/m² per side depending on the
quality. With a decreasing coating quantity, also the gloss may decrease as well as the
uniformity of the coat (cloudy formation) and the smoothness.
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15. Classification of papers coated on both sides for the sheet
and web offset printing
• LLWC/ULWC papers
Light Light Weight Coated Paper
Ultra Low Weight Coated Paper
Ultra-light Coated Paper
Wood-containing, with secondary fibres produced paper.
Basis weight 35-51 g/m² - coating weight : 5-10 g/m²
Especially for web offset printing.
• LWC papers
Light Weight Coated Paper
Light Weight Coated Paper for runs in the web offset printing
Coated paper especially for the Heatset web offset printing.
Basis weight: 51-73 g/m² - coating weight: 10-20 g/m²
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16. Classification of papers coated on both sides for the sheet
and web offset printing
• MWC/HWC papers
Medium Weight Coated Paper
Heavy Weight Coated Paper
Wood-Containing Coated Paper
Coated papers in the basis mass of 70-170 g/m².
Coating weight: 15-20 g/m² per side. They are also called picture printing or
specially coated papers.
• Cast-coated papers
Wood-free papers of high quality for labels, packing, envelops and folders.
Very high gloss, mostly cast-coated on one side.
Basis weight: 70-400 g/m² - coating weight: above 25 g/m².
White, coloured and with a metallic surface.
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17. Uncoated papers (natural papers) for the web offset
printing
• WSOP paper (Web Special Offset Paper)
Wood-containing paper, calendered uncoated paper for web offset printing.
• SC paper (= Super Calender)
Wood-containing, uncoated paper with high smoothness by glazing.
Especially for the web offset printing.
• B pulp paper
Uncoated, glazed paper for web offset printing. Compound of the pulp: wood
pulp, ground wood pulp and fillers. The brightness is determined.
• Newspaper printing paper
Uncoated paper mainly produced from secondary fibres (used paper). Here,
difference is made between “standard” and “improved”. Basis weight: 39 to
50 g/m². The smoothness, the absorbency, the colouring and the opacity are
especially of importance for the printability.
• Continuous papers
Wood-free to slightly wood-containing and also with more or less secondary
fibres. For text and data processing. The properties are determined in DIN
6721.
• SC-HSWO papers (Super Calendered Heavy Special Web Offset Papier)
= calendered, uncoated paper with high basis mass (basis weight).
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18. Technical Support
Sappi Fine Paper Europe
In case of questions or remarks
contact Oliver Kropacek
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