Printing by the numbers
Petter Kolseth
Luc Lanat, Örjan Sävborg
Stora Enso
Sweden & France
petter.i.kolseth@storaenso.com
www.storaenso.com
36th International Research Conference
Stockholm, Sweden

Printing by the numbers on commercial paper
Petter Kolseth, Luc Lanat, Örjan Sävborg

Standardised Print
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 3

Standardised Print
So where was the Paper Industry…?
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 4

Standardised Print – Why Now?
• Fogra offset process standards
date back to the 1980’s
• ISO 12647-2 appeared first in 1996
• Paper sales was approached by printers only over last couple of years
• Print is moving towards an industrial process
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 5

Potential sources for confusion and debate
• "Numbers" in the ISO standards
– Paper shade
– Primary and secondary colours
– Tone Value Increase – tonal transfer
• Measurement conditions and calibration procedures
– Paper industry: D65/10°, C/2°, D50/2°
– Graphic industry: M0, M1, M2, M3
• Paper fluorescence
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 6

Sheet offset on coated woodfree
Standardised Print
• Market follow-up on 50 European papers
– Paper Type 1 and 2
• Comparison of 10 inks on three papers
– Gloss, silk, matt (Type 1 and 2)
Gretag Spectrolino Scanning densitometer Print layout
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 7

Ludovic Coppel, Innventia
Paper shade

Print substrate colour and gloss
ISO 12647-2: Offset lithography
• Five typical paper types and their shade/colour and gloss:
Paper type L* a* b* gloss
1. Gloss-coated, woodfree 93(95) 0(0) -3(-2) 65
2. Matte-coated, woodfree 92(94) 0(0) -3(-2) 38
3. Gloss-coated, web 87(92) -1(0) 3(5) 55
4. Uncoated, white 92(95) 0(0) -3(-2) 6
5. Uncoated, slightly yellowish 88(90) 0(0) 6(9) 6
Tolerance ±3 ±2 ±2 ±5
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
– Black backing to allow for showthrough from reverse print
Values in brackets refer to white backing
Substrate backing (white) is standard in paper industry
– D50 illuminant, 2° observer, 0/45 or 45/0 geometry
D65/10° or C/2° and d/0° geometry is standard in paper industry
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 9

Print substrate used for proofing
ISO 12647-2: Offset lithography
• Print substrate used for proofing – identical to that of the production
• If not possible – close match in colour, gloss, surface grammage
• Press proofing on closest match to five typical paper surface types
• Proof substrate to conform … to attributes in Table 1 of the paper type
representing the production paper
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Paper type L* a* b* gloss
1. Gloss-coated, woodfree 93(95) 0(0) -3(-2) 65
2. Matte-coated, woodfree 92(94) 0(0) -3(-2) 38
3. Gloss-coated, web 87(92) -1(0) 3(5) 55
4. Uncoated, white 92(95) 0(0) -3(-2) 6
5. Uncoated, slightly yellowish 88(90) 0(0) 6(9) 6
Tolerance ±3 ±2 ±2 ±5
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 10

Paper shade – Elrepho D65/10°
Paper Type 1 – 90-250 gsm
0
-1
Measurements according
-2 to paper industry
-3 standard
CIELAB-b*
-4
-5
All products out-of-range
-6
-7
-8
-9
-10
-5 -4 -3 -2 -1 0 1 2 3 4 5
CIELAB-a*
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 11

Paper shade – Elrepho D65/10°
Paper Type 2 – 90-250 gsm
0
-1 Measurements according
-2 to paper industry
-3 standard
CIELAB-b*
-4
-5
All except one products
-6 out-of-range
-7
-8
-9
-10
-5 -4 -3 -2 -1 0 1 2 3 4 5
CIELAB-a*
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 12

Paper shade – Elrepho C/2°
Paper Type 1 – gloss 90-250 gsm
0
-1 Measurements according
-2 to "indoor whiteness"
-3 standard
CIELAB-b*
-4
-5
Some products in the box
-6
-7
-8
-9
-10
-5 -4 -3 -2 -1 0 1 2 3 4 5
CIELAB-a*
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 13

Paper shade – Spectrolino D50/2°
Paper Type 1 – 90-250 gsm
0
-1 Measurements according
-2 to printing industry
-3 standard
CIELAB-b*
-4 UV content not known
-5
Most products in the box
-6
-7
-8
-9
-10
-5 -4 -3 -2 -1 0 1 2 3 4 5
CIELAB-a*
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 14

Shades of double-coated glossy papers
More than 80% would fit into a proposed new recommended range
0,00
-1,00
-2,00
-3,00
CIELAB-b*
-4,00
-5,00
-6,00
-7,00
-8,00
-9,00
0,00 0,50 1,00 1,50 2,00 2,50
CIELAB-a*
Presentation WG3TF1 Paper Characterization (Bertholdt, ISO TC130 WG3, Bangkok 2007-05-15)
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 15

Paper shade – D65/10° - D50/2° - i1 D50/2°
Paper Type 2 – Silk-coated fine paper
20
Moderate fluorescence
15
The D65 UV setting high
10
enough to offset the b*
5
b*
0
-5
-10
-15
D50 i1D50 D65
-20
-20 -15 -10 -5 0 5 10 15 20
a*
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 16

Paper shade – D65/10° - D50/2° - i1 D50/2°
Paper Type 3 – Uncoated fine paper
20
Strong fluorescence
15
The D65 UV setting gives
10
even larger offset in b*
5
b*
0
-5
-10
-15
D50 i1D50 D65
-20
-20 -15 -10 -5 0 5 10 15 20
a*
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 17

Paper shade – D65/10° - D50/2° - i1 D50/2°
Paper Type 4 – Uncoated WoodFree without OBA
20
No fluorescence
15
D65 and D50 quite close,
10
but D50 slightly more red
5
b*
0
-5
-10
-15
D50 i1D50 D65
-20
-20 -15 -10 -5 0 5 10 15 20
a*
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 18

Conclusions – Paper Shade
A matter of taste – forget "ISO compliant"
ISO does not specify allowed shades
Should be determined with dedicated equipment
Most papers are within a narrow range of shades

Andreas Paul, FOGRA
Primaries and Secondaries

Colour gamut – Spectrolino D50/2°
Paper Type 1 and 2, gloss/matt/silk 90-250
100
Gloss b*
Matt/Silk 80
All prints rather close to
Target values
60
target colour CMYRGB
40
Original RGB targets
20
-a* a*
0
-100 -80 -60 -40 -20 0 20 40 60 80 100
-20
-40
-60
-80
-b*
-100
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 21

Colour gamut – Spectrolino D50/2°
Paper Type 1 and 2, gloss/matt/silk 90-250
100
b*
80
All prints very close to
60
target colour CMYRGB
40
After the 2004 Amendment
20
-a* a*
0
-100 -80 -60 -40 -20 0 20 40 60 80 100
-20
-40
-60
-80
-b*
-100
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 22

Ten inks on gloss, silk and matt paper
Colour gamut – Elrepho C/2°
100
Ten inks on Gloss paper CIE b*
Ten inks on Silk paper 80
Ten inks on Matt paper 30 ink-paper
60 combinations but almost
identical results
40
20
CIE -a* 0
CIE a*
-100 -80 -60 -40 -20 0 20 40 60 80 100
-20
-40
-60
-80
-100
CIE -b*
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 23

Conclusions – Primaries and Secondaries
No (or very small) influence of paper brand
Target colours can be reached with standard inks

Ludovic Coppel, Innventia
Paper fluorescence

Fluorescence – CIE Whiteness (D65)
70
60
Fluorescence (D65/10°)
50
40
30
20
10
100 110 120 130 140 150
CIE Whiteness (D65/10°) Gloss-Coated 200 – 350 gsm
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 26

CIE Whiteness – CIELAB-b* (D65)
150
140
CIE Whiteness (D65/10°)
130
120
110
100
-14 -12 -10 -8 -6 -4 -2 0
CIELAB-b* (D65/10°) Gloss-Coated 200 – 350 gsm
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 27

Primaries and Secondaries – Elrepho D65/10°
Paper Type 2 – Silk-coated fine paper
Elrepho D65/10°
100
80
60
40
b*
20
0
-20
-40
-60
-80 -60 -40 -20 0 20 40 60 80
a*
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 28

Primaries and Secondaries – i1 D50/2°
Paper Type 2 – Silk-coated fine paper
100
80
60
40
b*
20
0
-20
-40
-60
-80 -60 -40 -20 0 20 40 60 80
a*
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 29

Primaries and Secondaries – D50/2°
Paper Type 2 – Silk-coated fine paper
Elrepho D50/2°
100
80
60
40
b*
20
0
-20
-40
-60
-80 -60 -40 -20 0 20 40 60 80
a*
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 30

Primaries and Secondaries – D50/2° UV excluded
Paper Type 2 – Silk-coated fine paper
Elrepho D50/2° UV excluded
100
80
60
40
b*
20
0
-20
-40
-60
-80 -60 -40 -20 0 20 40 60 80
a*
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 31

Spectral power and Relative UV content
Illuminants D65, C, D50, A
Relative to 560 nm (max colour vision) Relative to 440 nm fluorescence peak
300 2,00
1,75
250
1,50
Spectral Power
200
Spectral Power
1,25
150 1,00
0,75
100
0,50
50
0,25
0 0,00
350 400 450 500 550 600 650 700 750 340 360 380 400 420 440 460 480 500 520 540 560
Wavelength, nm Wavelength, nm
D65 C D50 A D65rel Crel D50rel Arel
Relative power of A is almost twice that of C between 340 and 380 nm
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 32

Illumination is NOT same as Illuminant
Illumination 5000K and Illuminant D50
D50
2 D65
5000K CCT
5000K CCT + UV
Relative Power
1,5
1
0,5
0
300 350 400 450 500 550 600 650 700 750
Wavelength (nm) Ludovic Coppel, Innventia, 2008
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 33

Proof substrates from one supplier
x-rite iOne – a*-b* data
6,0
Red symbols denote
4,0 certified proof substrates
2,0
Green symbols denote production
0,0 paper PT2 and PT4
CIELAB-b*
-2,0
Type 2
-4,0
-6,0
Type 4
-8,0
-10,0
-12,0
-14,0
-2,0 -1,5 -1,0 -0,5 0,0 0,5 1,0 1,5 2,0 2,5 3,0
CIELAB-a*
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 34

Conclusions – Paper Fluorescence
Fluorescence make papers whiter (more blue)
Effect is very dependent on illumination
Fluorescence shines through all print
Matching proof to print with proper choice of
proof substrate and illumination

Tone Value Increase

Tone Value Increase: Black and Cyan
Paper Type 1 – 90-250 gsm
30% 30%
25% 25%
Black Tone Value Increase
Cyan Tone Value Increase
20% 20% +/- 4 20% 20% +/- 4
15% 15%
10% 10%
5% 5%
0% 0%
0% 20% 40% 60% 80% 100% 0% 20% 40% 60% 80% 100%
Nominal tone Nominal tone
Black and Cyan Dot Gain are both within tolerance
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 37

Optical dot gain
Effect on tone value and colour
AM
FM
after Matthieu Bossan, Creo, 2002
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 38

Reflectance histograms of K100, K40 and paper white
13,2% TVI(40)
2,5 25,0
2,0 20,0
Frequency, %
1,5 15,0
1,0 10,0
0,5 5,0
0,0 0,0
0 20 40 60 80 100
Reflectance, %
<K40> <BLACK> <WHITE>
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 39

Reflectance histograms of K100, K40 and paper white
20,1% TVI(40)
2,5 25,0
2,0 20,0
Frequency, %
1,5 15,0
1,0 10,0
0,5 5,0
0,0 0,0
0 20 40 60 80 100
Reflectance, %
<K40> <BLACK> <WHITE>
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 40

Reflectance histograms of K100, K40 and paper white
13,2% TVI(40)
2,5 25,0
Halftone dots Between dots
2,0 20,0
Frequency, %
1,5 15,0
Unimaged
Solid black
paper
1,0 10,0
0,5 5,0
0,0 0,0
0 20 40 60 80 100
Reflectance, %
<K40> <BLACK> <WHITE>
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 41

Reflectance histograms of K100, K40 and paper white
20,1% TVI(40)
2,5 25,0
Halftone dots
2,0 20,0
Unimaged
Frequency, %
paper
1,5 15,0
Between
Solid black
dots
1,0 10,0
0,5 5,0
0,0 0,0
0 20 40 60 80 100
Reflectance, %
<K40> <BLACK> <WHITE>
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 42

Black halftone seen in the microscope
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 43

Thresholding between peaks in histogram
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 44

Tone Value comparison
Densitometer readings vs. microscopy
56
Microscopy Tone Value
54
52
50
48
46
50 52 54 56 58 60 62 64
Densitometer Tone Value
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 45

Optical Tone Value Increase
Tone Values by microscopy
10,0
Single-coat matt
8,0
Optical TVI
multicoat
6,0
gloss multicoat silk
4,0
2,0
0,0
-20 -15 -10 -5 0
Reduction in paper reflectance between dots
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 46

Conclusions – Tone Value Increase
Mechanical TVI is small (in the ideal case)
Optical TVI is quite large
Optical TVI is an inherent paper property
(but not related to brand)
TVI variations are mechanical due to press settings

What is next?
Luc LANAT Stora Enso PrintNet at iarigai Stockholm Sept 2009

Optics – What next?
• To define (White) Paper shade targets
– Use ISO 5631-1 or 2 Colour L*a*b* C/2° or D65/10°
• ISO 13655-2009 must not be used to specify (white) papers
– Use ISO 5631-3 Colour L*a*b* D50/2°
• To evaluate Fluorescence in papers
– Use ISO 2470-2 (Note 8.4) on D65 Brightness
– Use ISO 11476 (Note 10.3), ISO 11475 (Clause 10.3). Whiteness
• Organize UV calibration of D50 illuminant is a MUST
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 49

Dot Gain – TVI
• ISO TS 10128-2008 « Methods of adjustment of the colour reproduction
of a printing system to match a set of characterisation data »
– When measuring quality of a print thru reflectance, you are indeed
integrating all variations, variations coming from base, thus paper,
variations coming from inks, from press, etc…
– To define Dot Gain or TVI of a paper is a misunderstanding
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 50

Standardization – What next?
• There is no ISO compliant paper
– See Paperdam statement Sept 2009
– We recommend publicly available colour profiles and
characterization data (ECI, PSR, FOGRA…)
• ISO TC 6 Berlin, support creation of NWI
– Develop ISO 5630-7, aging under light conditions to evaluate light
fastness
– Develop D 50 UV calibration rules
• ISO TC 130 Beijing, support creation of NWI
– How to measure proof papers
– JWG (joint working group) liaison TC 6 – TC 130
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 51

The last slide – 3 points
• The daily challenge in a paper mill is to fulfil paper specifications
communicated in Technical Data Sheets, in this order
– Brightness and shade
– Smoothness (PPS,…)
– Gloss
– Anything to satisfy printing results at printer
• Process Management at printer and at papermaker is the topic
– For a given grade, work on process consistency and not on
upgrade of paper definition to reach better printed results
• It is common interest of all players in this market to help standardization
and support quality of printed media at lowest cost
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 52

Thank You