Iarigai kolseth lanat savborg printing by-the-numbers stockholm 2009 presentation

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
Petter Kolseth, Luc Lanat, Örjan Sävborg
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…?

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

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

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)
Scanning densitometer Gretag Spectrolino Print layout

Paper shade
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

Print substrate used for proofing
• Five typical paper types and their shade/colour and gloss:
3. Gloss-coated, web 87(92) -1(0) 3(5) 55
4. Uncoated, white 92(95) 0(0) -3(-2) 6
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
• 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

Print substrate used for proofing
• 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
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
3. Gloss-coated, web 87(92) -1(0) 3(5) 55
4. Uncoated, white 92(95) 0(0) -3(-2) 6

Paper shade – Elrepho D65/10°
Paper Type 1 – 90-250 gsm
0
-1
-2
-3
-4
-5
-6
-7
-8
-9
-10
-5 -4 -3 -2 -1 0 1 2 3 4 5
CIELAB-a*
CIELAB-b*
Measurements according
to paper industry
standard
All products out-of-range

Paper shade – Elrepho D65/10°
0
-1
-2
-3
-4
-5
-6
-7
-8
-9
-10
-5 -4 -3 -2 -1 0 1 2 3 4 5
CIELAB-a*
CIELAB-b*
to paper industry
standard
All except one products
out-of-range

Paper shade – Elrepho C/2°
Paper Type 1 – gloss 90-250 gsm
to "indoor whiteness"
standard
Some products in the box
0
-1
-2
-3
-4
-5
-6
-7
-8
-9
-10
-5 -4 -3 -2 -1 0 1 2 3 4 5
CIELAB-a*
CIELAB-b*

Paper shade – Spectrolino D50/2°
0
-1
-2
-3
-4
-5
-6
-7
-8
-9
-10
-5 -4 -3 -2 -1 0 1 2 3 4 5
CIELAB-a*
CIELAB-b*
to printing industry
standard
UV content not known
Most products in the box

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
-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*
CIELAB-b*
Presentation WG3TF1 Paper Characterization (Bertholdt, ISO TC130 WG3, Bangkok 2007-05-15)

Paper shade – D65/10°- D50/2°- i1 D50/2°
Paper Type 2 – Silk-coated fine paper
20
15
10
5
0
-5
-10
-15
-20
D50 i1D50 D65
-20 -15 -10 -5 0 5 10 15 20
a*
b*
Moderate fluorescence
The D65 UV setting high
enough to offset the b*

Paper shade – D65/10°- D50/2°- i1 D50/2°
Paper Type 3 – Uncoated fine paper
20
15
10
5
0
-5
-10
-15
-20
D50 i1D50 D65
-20 -15 -10 -5 0 5 10 15 20
a*
b*
Strong fluorescence
The D65 UV setting gives
even larger offset in b*

Paper shade – D65/10°- D50/2°- i1 D50/2°
Paper Type 4 – Uncoated WoodFree without OBA
20
15
10
5
0
-5
-10
-15
-20
D50 i1D50 D65
-20 -15 -10 -5 0 5 10 15 20
a*
b*
No fluorescence
D65 and D50 quite close,
but D50 slightly more red

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

Primaries and Secondaries
Primaries and Secondaries
Andreas Paul, FOGRA

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

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

Ten inks on gloss, silk and matt paper
Colour gamut – Elrepho C/2°
100
Ten inks on Gloss paper
Ten inks on Silk paper
80
Ten inks on Matt paper 30 ink-paper
60
40
20
CIE b*
CIE -a* CIE a*
0
-100 -80 -60 -40 -20 0 20 40 60 80 100
-20
-40
-60
-80
-100
CIE -b*
combinations but almost
identical results

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

Paper fluorescence
Paper fluorescence
Ludovic Coppel, Innventia

Fluorescence – CIE Whiteness (D65)
100 110 120 130 140 150
Gloss-Coated 200 – 350 gsm
70
60
50
40
30
20
10
CIE Whiteness (D65/10°)
Fluorescence (D65/10°)

CIE Whiteness – CIELAB-b* (D65)
-14 -12 -10 -8 -6 -4 -2 0
Gloss-Coated 200 – 350 gsm
150
140
130
120
110
100
CIELAB-b* (D65/10°)
CIE Whiteness (D65/10°)

Primaries and Secondaries – Elrepho D65/10°
Elrepho D65/10°
100
80
60
40
20
0
-20
-40
-60
-80 -60 -40 -20 0 20 40 60 80
a*
b*

Primaries and Secondaries – i1 D50/2°
100
80
60
40
20
0
-20
-40
-60
-80 -60 -40 -20 0 20 40 60 80
a*
b*

Primaries and Secondaries – D50/2°
Elrepho D50/2°
100
80
60
40
20
0
-20
-40
-60
-80 -60 -40 -20 0 20 40 60 80
a*
b*

Primaries and Secondaries – D50/2°UV excluded
Elrepho D50/2°UV excluded
100
80
60
40
20
0
-20
-40
-60
-80 -60 -40 -20 0 20 40 60 80
a*
b*

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

Illumination is NOT same as Illuminant
Illumination 5000K and Illuminant D50
Ludovic Coppel, Innventia, 2008
2
1,5
1
0,5
0
D50
D65
5000K CCT
5000K CCT + UV
300 350 400 450 500 550 600 650 700 750
Wavelength (nm)
Relative Power

CIELAB-b* Proof substrates from one supplier
x-rite iOne – a*-b* data
6,0
4,0
2,0
0,0
-2,0
-4,0
-6,0
-8,0
-10,0
-12,0
-14,0
Type 2
Type 4
-2,0 -1,5 -1,0 -0,5 0,0 0,5 1,0 1,5 2,0 2,5 3,0
CIELAB-a*
Red symbols denote
certified proof substrates
Green symbols denote production
paper PT2 and PT4

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

Tone Value Increase: Black and Cyan
30%
25%
20%
15%
10%
5%
0%
20% +/- 4
Cyan Tone Value Increase
0% 20% 40% 60% 80% 100%
Nominal tone
Black Tone Value Increase
30%
25%
20%
15%
10%
5%
0%
20% +/- 4
0% 20% 40% 60% 80% 100%
Black and Cyan Dot Gain are both within tolerance
Nominal tone

Optical dot gain
Effect on tone value and colour
after Matthieu Bossan, Creo, 2002
AM
FM

Reflectance histograms of K100, K40 and paper white
13,2% TVI(40)
2,5
2,0
1,5
1,0
0,5
0,0
25,0
20,0
15,0
10,0
5,0
0 20 40 60 80 100
Reflectance, %
Frequency, %
0,0
<K40> <BLACK> <WHITE>

20,1% TVI(40)
2,5
2,0
1,5
1,0
0,5
0,0
25,0
20,0
15,0
10,0
5,0
0 20 40 60 80 100
Reflectance, %
Frequency, %
0,0

13,2% TVI(40)
2,5
2,0
1,5
1,0
0,5
0,0
25,0
20,0
15,0
10,0
5,0
0,0
Halftone dots Between dots
Solid black
Unimaged
paper
0 20 40 60 80 100
Reflectance, %
Frequency, %

20,1% TVI(40)
2,5
2,0
1,5
1,0
0,5
0,0
25,0
20,0
15,0
10,0
5,0
0,0
Halftone dots
Solid black
Between
dots
Unimaged
paper
0 20 40 60 80 100
Reflectance, %
Frequency, %

Black halftone seen in the microscope

Thresholding between peaks in histogram

Tone Value comparison
Densitometer readings vs. microscopy
56
54
52
50
48
46
50 52 54 56 58 60 62 64
Densitometer Tone Value
Microscopy Tone Value

Optical Tone Value Increase
Tone Values by microscopy
10,0
8,0
6,0
4,0
2,0
0,0
Single-coat matt
multicoat
gloss multicoat silk
-20 -15 -10 -5 0
Reduction in paper reflectance between dots
Optical TVI

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

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

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

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

Iarigai kolseth lanat savborg printing by-the-numbers stockholm 2009 presentation

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