Printing by the numbers
Petter Kolseth
Luc Lanat, Örjan Sävborg
Stora EnsoSweden & [email protected]
36th International Research ConferenceStockholm, Sweden
Printing by the numbers on commercial paperPetter Kolseth, Luc Lanat, Örjan Sävborg
Printing by the numbersPetter Kolseth, Luc Lanat, Örjan Sävborg
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 3
Standardised Print
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 4
Standardised Print
So where was the Paper Industry…?
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 5
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 6
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 7
Sheet offset on coated woodfreeStandardised 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 Print layoutGretag Spectrolino
Paper shadeLudovic Coppel, Innventia
Paper shade
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 9
Print substrate colour and glossISO 12647-2: Offset lithography
• Five typical paper types and their shade/colour and gloss: Paper type L* a* b* gloss1. Gloss-coated, woodfree 93(95) 0(0) -3(-2) 652. Matte-coated, woodfree 92(94) 0(0) -3(-2) 383. Gloss-coated, web 87(92) -1(0) 3(5) 554. Uncoated, white 92(95) 0(0) -3(-2) 65. Uncoated, slightly yellowish 88(90) 0(0) 6(9) 6Tolerance ±3 ±2 ±2 ±5----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
– Black backing to allow for showthrough from reverse printValues in brackets refer to white backingSubstrate backing (white) is standard in paper industry
– D50 illuminant, 2°observer, 0/45 or 45/0 geometryD65/10°or C/2°and d/0°geometry is standard in paper industry
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 10
Print substrate used for proofingISO 12647-2: Offset lithography
• Five typical paper types and their shade/colour and gloss: Paper type L* a* b* gloss1. Gloss-coated, woodfree 93(95) 0(0) -3(-2) 652. Matte-coated, woodfree 92(94) 0(0) -3(-2) 383. Gloss-coated, web 87(92) -1(0) 3(5) 554. Uncoated, white 92(95) 0(0) -3(-2) 65. Uncoated, slightly yellowish 88(90) 0(0) 6(9) 6Tolerance ±3 ±2 ±2 ±5----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
• 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
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 11
Print substrate used for proofingISO 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* gloss1. Gloss-coated, woodfree 93(95) 0(0) -3(-2) 652. Matte-coated, woodfree 92(94) 0(0) -3(-2) 383. Gloss-coated, web 87(92) -1(0) 3(5) 554. Uncoated, white 92(95) 0(0) -3(-2) 65. Uncoated, slightly yellowish 88(90) 0(0) 6(9) 6Tolerance ±3 ±2 ±2 ±5
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 12
-10
-9
-8
-7
-6
-5
-4
-3
-2
-1
0
-5 -4 -3 -2 -1 0 1 2 3 4 5
CIELAB-a*
CIE
LAB
-b*
Paper shade – Elrepho D65/10°Paper Type 1 – 90-250 gsm
Measurements according to paper industry standard
All products out-of-range
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 13
-10
-9
-8
-7
-6
-5
-4
-3
-2
-1
0
-5 -4 -3 -2 -1 0 1 2 3 4 5
CIELAB-a*
CIE
LAB
-b*
Paper shade – Elrepho D65/10°Paper Type 2 – 90-250 gsm
Measurements according to paper industry standard
All except one products out-of-range
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 14
Paper shade – Elrepho C/2°Paper Type 1 – gloss 90-250 gsm
Measurements according to "indoor whiteness" standard
Some products in the box
-10
-9
-8
-7
-6
-5
-4
-3
-2
-1
0
-5 -4 -3 -2 -1 0 1 2 3 4 5
CIELAB-a*
CIE
LAB
-b*
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 15
-10
-9
-8
-7
-6
-5
-4
-3
-2
-1
0
-5 -4 -3 -2 -1 0 1 2 3 4 5
CIELAB-a*
CIE
LAB
-b*
Paper shade – Spectrolino D50/2°Paper Type 1 – 90-250 gsm
Measurements according to printing industry standard
UV content not known
Most products in the box
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 16
-9,00
-8,00
-7,00
-6,00
-5,00
-4,00
-3,00
-2,00
-1,00
0,00
0,00 0,50 1,00 1,50 2,00 2,50
CIELAB-a*
CIE
LAB
-b*
Shades of double-coated glossy papers More than 80% would fit into a proposed new recommended range
Presentation WG3TF1 Paper Characterization (Berthol dt, ISO TC130 WG3, Bangkok 2007-05-15)
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 17
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
-20 -15 -10 -5 0 5 10 15 20
a*
b*
D50 i1D50 D65
Moderate fluorescence
The D65 UV setting high enough to offset the b*
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 18
Paper shade – D65/10°- D50/2°- i1 D50/2°Paper Type 3 – Uncoated fine paper
-20
-15
-10
-5
0
5
10
15
20
-20 -15 -10 -5 0 5 10 15 20
a*
b*
D50 i1D50 D65
Strong fluorescence
The D65 UV setting gives even larger offset in b*
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 19
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
-20 -15 -10 -5 0 5 10 15 20
a*
b*
D50 i1D50 D65
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 SecondariesAndreas Paul, FOGRA
Primaries and Secondaries
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 22
Colour gamut – Spectrolino D50/2°Paper Type 1 and 2, gloss/matt/silk 90-250
-100
-80
-60
-40
-20
0
20
40
60
80
100
-100 -80 -60 -40 -20 0 20 40 60 80 100
a*-a*
-b*
b*GlossMatt/Silk
Target valuesAll prints rather close to target colour CMYRGB
Original RGB targets
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 23
Colour gamut – Spectrolino D50/2°Paper Type 1 and 2, gloss/matt/silk 90-250
-100
-80
-60
-40
-20
0
20
40
60
80
100
-100 -80 -60 -40 -20 0 20 40 60 80 100
a*-a*
-b*
b*
All prints very close to target colour CMYRGB
After the 2004 Amendment
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 24
Ten inks on gloss, silk and matt paperColour gamut – Elrepho C/2°
-100
-80
-60
-40
-20
0
20
40
60
80
100
-100 -80 -60 -40 -20 0 20 40 60 80 100
CIE a*CIE -a*
CIE b*
CIE -b*
Ten inks on Gloss paper
Ten inks on Silk paper
Ten inks on Matt paper 30 ink-paper 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 fluorescenceLudovic Coppel, Innventia
Paper fluorescence
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 27
Fluorescence – CIE Whiteness (D65)
Gloss-Coated 200 – 350 gsm
10
20
30
40
50
60
70
100 110 120 130 140 150
CIE Whiteness (D65/10°)
Flu
ores
cenc
e (D
65/1
0°)
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 28
CIE Whiteness – CIELAB-b* (D65)
Gloss-Coated 200 – 350 gsm
100
110
120
130
140
150
-14 -12 -10 -8 -6 -4 -2 0
CIELAB-b* (D65/10°)
CIE
Whi
tene
ss (
D65
/10°
)
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 29
Primaries and Secondaries – Elrepho D65/10°Paper Type 2 – Silk-coated fine paper
-60
-40
-20
0
20
40
60
80
100
-80 -60 -40 -20 0 20 40 60 80
a*
b*
Elrepho D65/10°
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 30
Primaries and Secondaries – i1 D50/2°Paper Type 2 – Silk-coated fine paper
-60
-40
-20
0
20
40
60
80
100
-80 -60 -40 -20 0 20 40 60 80
a*
b*
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 31
Primaries and Secondaries – D50/2°Paper Type 2 – Silk-coated fine paper
-60
-40
-20
0
20
40
60
80
100
-80 -60 -40 -20 0 20 40 60 80
a*
b*
Elrepho D50/2°
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 32
Primaries and Secondaries – D50/2°UV excludedPaper Type 2 – Silk-coated fine paper
-60
-40
-20
0
20
40
60
80
100
-80 -60 -40 -20 0 20 40 60 80
a*
b*
Elrepho D50/2°UV excluded
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 33
Spectral power and Relative UV contentIlluminants D65, C, D50, A
0
50
100
150
200
250
300
350 400 450 500 550 600 650 700 750
Wavelength, nm
Spe
ctra
l Pow
er
D65 C D50 A
Relative to 560 nm (max colour vision)
0,00
0,25
0,50
0,75
1,00
1,25
1,50
1,75
2,00
340 360 380 400 420 440 460 480 500 520 540 560
Wavelength, nmS
pect
ral P
ower
D65rel Crel D50rel Arel
Relative to 440 nm fluorescence peak
Relative power of A is almost twice that of C betwe en 340 and 380 nm
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 34
Illumination is NOT same as Illuminant Illumination 5000K and Illuminant D50
Ludovic Coppel, Innventia, 2008
300 350 400 450 500 550 600 650 700 7500
0,5
1
1,5
2
Wavelength (nm)
Rel
ativ
e P
ower
D50D655000K CCT5000K CCT + UV
300 350 400 450 500 550 600 650 700 7500
0,5
1
1,5
2
Wavelength (nm)
Rel
ativ
e P
ower
D50D655000K CCT5000K CCT + UV
D50D655000K CCT5000K CCT + UV
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 35
-14,0
-12,0
-10,0
-8,0
-6,0
-4,0
-2,0
0,0
2,0
4,0
6,0
-2,0 -1,5 -1,0 -0,5 0,0 0,5 1,0 1,5 2,0 2,5 3,0
CIELAB-a*
CIE
LAB
-b*
Proof substrates from one supplierx-rite iOne – a*-b* data
Red symbols denote certified proof substrates
Green symbols denote production paper PT2 and PT4
Type 2
Type 4
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
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 38
Tone Value Increase: Black and CyanPaper Type 1 – 90-250 gsm
Black and Cyan Dot Gain are both within tolerance
0%
5%
10%
15%
20%
25%
30%
0% 20% 40% 60% 80% 100%
Nominal tone
Bla
ck T
one
Val
ue In
crea
se
20% +/- 4
0%
5%
10%
15%
20%
25%
30%
0% 20% 40% 60% 80% 100%
Nominal tone
Cya
n T
one
Val
ue In
crea
se
20% +/- 4
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 39
Optical dot gainEffect on tone value and colour
after Matthieu Bossan, Creo, 2002
AM
FM
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 40
Reflectance histograms of K100, K40 and paper white13,2% TVI(40)
0,0
0,5
1,0
1,5
2,0
2,5
0 20 40 60 80 100
Reflectance, %
Fre
quen
cy, %
0,0
5,0
10,0
15,0
20,0
25,0
<K40> <BLACK> <WHITE>
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 41
Reflectance histograms of K100, K40 and paper white20,1% TVI(40)
0,0
0,5
1,0
1,5
2,0
2,5
0 20 40 60 80 100
Reflectance, %
Fre
quen
cy, %
0,0
5,0
10,0
15,0
20,0
25,0
<K40> <BLACK> <WHITE>
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 42
0,0
0,5
1,0
1,5
2,0
2,5
0 20 40 60 80 100
Reflectance, %
Fre
quen
cy, %
0,0
5,0
10,0
15,0
20,0
25,0
<K40> <BLACK> <WHITE>
Reflectance histograms of K100, K40 and paper white13,2% TVI(40)
Solid black
Halftone dots Between dots
Unimagedpaper
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 43
0,0
0,5
1,0
1,5
2,0
2,5
0 20 40 60 80 100
Reflectance, %
Fre
quen
cy, %
0,0
5,0
10,0
15,0
20,0
25,0
<K40> <BLACK> <WHITE>
Reflectance histograms of K100, K40 and paper white20,1% TVI(40)
Solid black
Halftone dots
Between dots
Unimagedpaper
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 44
Black halftone seen in the microscope
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 45
Thresholding between peaks in histogram
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 46
Tone Value comparisonDensitometer readings vs. microscopy
46
48
50
52
54
56
50 52 54 56 58 60 62 64
Densitometer Tone Value
Mic
rosc
opy
Ton
e V
alue
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 47
0,0
2,0
4,0
6,0
8,0
10,0
-20 -15 -10 -5 0
Reduction in paper reflectance between dots
Opt
ical
TV
IOptical Tone Value Increase Tone Values by microscopy
Single-coat matt
multicoat gloss multicoat silk
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
September 2009 Printing by the numbers / Kolseth-Lanat-Sävborg 50
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 51
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 52
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 53
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
Thank You
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