Paper Categorization Meeting ICC/ISO TC June 2006 Hilton Leeds City Neville Street Leeds, England

Transcription

1 Paper Categorization Meeting ICC/ISO TC June 2006 Hilton Leeds City Neville Street Leeds, England Craig Revie began the meeting at 8.30am, when participants introduced themselves and described their reasons for being at the meeting. The agenda [see attached] was agreed with some minor updates A wide range of companies were represented, with most participants from paper manufacturing, printers and prepress, with a small number of ink manufacturers and print buyers. The full list of participants is attached. Presentations were made on a number of topics relevant to paper classification. The first, by David McDowell [see attached], described the need for paper properties in the context of color management. The goal was to understand more about paper properties in order to reduce the need to generate characterization data for each print/paper combination. He concluded by posing a number of key issues for discussion: - What should be measured? - How should tests be developed? -How should the approach be evaluated? - Are there other possible approaches? It was noted that the existing classification categories contained wide ranges of paper types; for example, the uncoated category includes premium papers for fine art reproduction as well as basic office grades. These US text and cover grades are not included in the paper types specified in ISO In the US, quality grades are linked strongly to the paper reflectance property for historic reasons, whereas in Europe categories are based mainly on the manufacturing process used. Hence properties do not correlate internationally. Fluorescence in paper leads to problems in color management, since the instrument source used for measuring reflectance will normally have less UV content than the viewing illumination. Re-emission from the substrate was generally proportional to the amount of fluorescent whitening additive (FWA) present. Paper gloss expands the color gamut in darker colors and shadow areas, although this is not best captured by the 0:45 measurement geometry which excludes specular reflectance. Otherwise gloss and matte papers have similar shades, and are not differentiated by wood content.

2 In consequence of these issues, there is a need to consider new ways of classifying paper. For the purpose of process control, gloss and matte papers have very similar CIELAB values and do not require separate categories. Karl Meinecke noted that the same characterization data was being used for both paper types 1 and 2 in ISO Byron Jordan noted that whiteness is by definition associated with CIELAB b*, as a result of the way that CIE whiteness is calculated. Jouni Martilla made a presentation on problems with current paper categories [see attached]. Since paper grades were less clearly demarcated in the current market, there was a need to review the classification used in ISO The web offset grades do not include the higherquality papers being used, and there is a need for more web grades in the standard. He demonstrated that there is a big range in shade and luminance in the papers currently on the market. The matte grade in ISO actually relates better to silk grades on the market, and the difference between silk and gloss is much smaller than between silk and true matte papers. The main paper-related property affecting color was ink demand; this was affected by the surface roughness and oil absorption properties of the paper. Byron Jordan observed that paper chemistry was also important. Danny Rich presented information on paper parameters that affect color reproduction [see attached]. In this he noted that the ink absorption had a significant effect on color gamut. Karl Meinecke presented a summary of paper classifications for gravure and offset [see attached ] and supporting papers on a proposed categorization for offset papers and gravure papers [see attached]. Characterization data is available for some of these categories. The classification of gravure papers is available (in German) from An English version will be available at this site in a couple of days. It was observed that paper type 5 could be dropped from ISO as it was no longer important. It was agreed that it was important to reduce the number of categories as much as possible. Trish Wales and Anne-Sophie Gombart presented information on paper classification properties, ISO and regional differences in paper manufacture. [see attached] Trish Wales also presented information on brightness classifications [see attached}. She clarified that there were two different standard methods for measuring brightness, using Illuminants C and D65 respectively, the latter giving a higher numerical value. Karl Meinecke stated that the D65 method had been used in the data presented. Craig Revie suggested that it was important that a worldwide consensus on paper categories is agreed even if we start by defining a set of categories appropriate for European users.

3 Nils Pauler of M-Real presented current activities in ISO TC 6-WG3 (Paper, board and pulp optical properties) [see attached]. He discussed the organization of the group and noted that he acts as liaison from TC6 to ICC. He also discussed instruments used in the paper industry and noted that calibration is a major issue. He reviewed the standards for reflectance measurements (see list in presentation) and highlighted the new ISO numbers and new methods for reflectance measurements. He then reviewed the calibration hierarchy for absolute reflectance measurements based on the perfect reflecting diffuser. This is important because all of the larger pulp and paper companies rely on ISO standards. He discussed a new color measurement method in ISO CD 5631 which he felt might initiate some discussion and perhaps some disagreement in the group. In summary, he asked if there is a need for common optical measurement methods, can we use the instruments of today and finally will there be new spectral scanners and or digital cameras in the future that will be useful for the paper industry. He mentioned a book entitled Color Engineering which was co-edited by Phil Green as an excellent source. How reliable are the measurements when you use different instruments? Mr Pauler found significant differences between devices in tests his company conducted. If you follow the ISO calibration methods, the difference between two instruments is about 2%. The calibration method provided by the instrument supplier is not sufficient and the ISO method should be used. Why differences in measuring under C and D65? There was a lot of history of doing measurements under C however after fluorescents was added to the standard, the measuring condition was changed to D65. This results in higher numerical brightness and whiteness values, and is therefore often preferred by the paper industry. Trish Wales reported on IDEAlliance which is a group that governs some of the standards within the graphic arts industry. She announced a new task force is being formed of 8 paper manufacturers, paper dist, publishers, printers and print buyers. They want to understand how to characterize paper in the printing process. The position paper of this group is included as attachment to these minutes. This group could be a good focal point for US companies to provide input into this process and develop a US view on paper characterization. Laurel Brunner felt that there were differences in how Europe and the US approached paper characterization and she hoped that this would change as we go forward. A presentation from UPM on the paper market was also made available to the meeting. [see attached].

4 Byron Jordan, chair of TC6 WG3, reported that the technologies used with optical measurement was broad and needed a separate group within TC6. It deals with reflectance, gloss and measurement of paper. TC6 deals with defining measurement processes and not measurement classifications. Sometimes classifications have been used as non-tariff barriers to trade. We need to recognize that each side of the paper issue, there is a rich literature and a lot of understanding but the two do not speak well to each other. There are good reasons why each performs measurements the way they do. The surface chemistry can be difficult to measure due to the contact angle on a rough surface being ill defined. This controls whether the ink will sit on top of the paper or be absorbed. The defining characteristic was whether or not the ink would flow within an area on the paper. Print gloss in not necessarily determined by paper gloss, the ideal being a matte paper with a high gloss. Print gloss enables high densities and print contrast to be achieved. Translucency deals with how far the light migrates within the sheet. Different papers have different ranges. This can affect measurements it is necessary over illuminate (i.e. have a measurement aperture smaller than the area illuminated) to adjust for this effect. Goneoreflectance is another issue affecting measurements which makes different instruments get different results due to the inherent geometry of the instruments. All of the above are reasons why the measurement methodology is defined as it is. The whiteness measurement deals with how much more radiance you have in the blue rather than the green. Dyes can be added to bring the reflectance of the green down which makes the paper appear whiter. For this reason, the standard deals with brightness more than whiteness. Fred Dolezalek presented properties of printing papers [see attached] and provided some specifications and basic requirements for data generation and the control of the printing process. He attempted to summarize what we heard during the presentations this morning. There are two areas where we need to know better properties of paper: Visual properties of the printing products relevant to prepress and on-press process control. This permits choice of characterization data and proofing substrate. Mechanical and other properties such as dimensions, mass per area, roughness, stiffness, etc. as this helps the printer so that he can better choose materials that are appropriate for his press and provides inputs for JDF. Visual properties require the paper color, surface type, gloss and opacity. To a lesser degree the degree of fluorescence and TVI as compared to a standard paper. He then showed 5 paper classes and their varying gamuts which varied greatly. Suggestions: he felt that the standards needed revision such as dropping PT5 and PT2 from the offset cats and add 2-3 new categories. The possible shift of paper colours to the blue and

5 making gloss informative as well as replacing the criterion of mass per are by opacity were other possible changes needed. For mechanical and other properties, there have been some tests conducted in Germany which are highlighted in his presentations. In closing, he encouraged the paper manufacturers to identify what classes their various papers are categorized as this would be a great aid to printers. The problem is that the classification of papers in various regions of the world could differ because the paper was measured according to different viewing conditions (D65 vs. D50). Jan-Peter Homann presented a proposal on Papertypes, gamuts, graybalance, TVI, NPDC, characterization-data and ICC-Profiles [see attached]. Following the final presentation, the chair then opened the meeting for discussion with a summary of the problem statement from the invitation document. Essentially it was difficult for the user to know whether the paper being used is sufficiently similar to that used in making the profile. Ann McCarthy suggested that it was important to capture printing characteristics for other applications such as office use. However, the meeting agreed that the focus of the meeting was paper for graphic arts applications and in particular ISO The need was felt to be to solve the core problem of publication and commercial printing. Dave McDowell observed that there was another standard which covered office papers. Laurel Brunner asked whether packaging grades were included, and the meeting decided that they should not be at this stage since that introduced a much wider range of categorization issues. Martilla Jouni asked whether if there just two paper categories for which unified characterization data could be generated, would it help the print buyer. Michael Farkas of IKEA responded that the profusion of categories makes it difficult for the specifier, who needs greater simplicity and hints as to how to order paper and apply color management. The question was asked what the reason was for the differences between shade preferences on different continents, with Europe significantly bluer than the US and Asia. A participant from Stora Enso responded that shades in the US were drifting towards those in Europe. There were differences in manufacturing processes between US and Europe, but paper makers were trying to meet customer preferences. She also noted that globalization may lead to a change in preferences and a reduction in the differences. Another participant noted that classification properties need to be based on what is actually used in the market for example, European papers are bluer than ISO shades. One participant commented that CIELAB was not sufficient for defining paper properties, and different shade categories were needed. He liked the matrix approach shown by some presenters, which may help the user select the correct paper.

6 Karl Meinecke suggested that a small number of classification properties were needed. The existing set of profiles was already difficult for customers to understand; maybe it should be an aim to edit a base profile rather than make new profiles. Fred Dolazelek stated that ISO was largely based on European input. Now we are in a better position to update the standard. He also observed that the shades specified in ISO were intended for proofing, but people expected to also use them in process control for production (where different tolerances apply). The market had developed since the ISO specification was published and it was certain that the paper types on the market will be different in another ten years. A participant commented that dot gain was one of the most important paper parameters. Tests held by user groups indicated that different papers from the same manufacturer could have 6-8% differences in dot gain when printed with the same solid density. Roughness was not the main variable, since papers of very different roughness could have the same range of dot gain. Bob Hallam suggested that the key factor that printers need is a metric for surface quality, including especially the ink demand. It was important to know in advance of production what the level of dot gain would be, for example to predict the volume of ink required by a job. Craig Revie responded that gamut was a limiting factor, while dot gain could be adjusted and was therefore a secondary measure. Uwe Berthold observed that fogra had recently developed a test method for tonal value increase using a printability tester, but had not been able to get results which agreed with production values. Fred Dolazelek commented that determining TVI in an absolute sense is difficult, and suggested that possibly relative TVI, compared against a standard paper, would make sense. The paper makers present noted that the characteristics of the standard paper would need to be known. Martilla Jouni reported on a large scale study which had been undertaken: for papers of the same basis weight printed by the same process, the coating and furnish affected the TVI. TVI is also affected by the compressibility of the paper surface, and since heavier basis weights of the same paper are smoother, there are TVI differences based solely on grammage. The chair then asked the meeting to turn to the question of how to take the issues discussed in the meeting forward. He proposed a working group with Uwe Berthold of fogra as coordinator. This was agreed by the meeting, with the proposal that the group should report to the next ISO TC130 meeting, recommending changes to the existing standards and any new standards which are required. Byron Jordan suggested that both papermakers and printers should be represented in this activity, and that it was important to have a range of participation to avoid privileging a single supplier. Trish Wales observed that there was a good synergy between this activity and that of the IDEAlliance initiative, and agreed to act as liaison between the two groups. Craig Revie suggested that formally the activity to define categories should be considered a TC130 and that

7 IDEAlliance should be encouraged to provide input to this group to ensure that US paper manufacturers and print buyers are well represented. He also suggested that the group should include a liaison with ISO TC 6. The following delegates agreed to participate in the working group: Michael Farks (IKEA) Byron Jordan (Paprican) Trish Wales (Sappi) Anne-Sophie Gombart (Sappi) Nevelle Bower (Felix Schoeller) Teuro Leppanen (UPM-Kymmene) David McDowell (Kodak) Bob Hallam (Quebecor World) Karl Meinecke (bvdm) John Davison (Davison Chemographics) Martin Gercke (Stora Enso) Peter Garnham (Polestar) Craig Revie (Fuji Photo Film) Jouna Martilla (M-real) Uwe Berthold noted that there was an ISO meeting in September. The working group should meet there, and he will plan to have a proposal for review at this meeting. Craig Revie noted that some people were not represented at the meeting, and it was important to include other interested parties such as Japanese paper suppliers. As guidance for other possible participants, it was agree to make available the meeting minutes and a mission statement from Uwe Berthold. Martilla Jouni suggested that we should make a priority of providing characterization data for new paper classes including high-brightness LWC, and emphasized that it was important to have common data for US and EU. Fred Dolazelek agreed but noted that it was not just technical information that was required. It was suggested that the ICC Graphic Arts Special Interest group could be a way of continuing discussion on the issue of reducing the number of characterization data sets. The chair thanked the participants and closed the meeting at 12.30pm.

8 Introductions and meeting aims Presentations Why paper categories are important for print characterisation David McDowell Paper parameters that affect colour reproduction Danny Rich Current paper categories and paper conformance Jouni Martilla / Trish Wales / Anne-Sophie Gombart Paper categories in publication gravure printing and vision for sheet and web offset printing K. M. Meinecke / Jan-Peter Homann Current activities in other ISO groups Nils Pauler IDEAlliance Print Predictability Paper Taskforce Trish Wales Measurement issues addressed by ISO TC6 WG3 Byron Jordan Paper properties: specifications, basic requirements for data generation and control of printing processes Fred. Dolezalek Discussion Summary of action items Plans for subsequent meeting Other business Adjourn

9 Problem statement Users often need to know which ICC Profile is appropriate for a given printing condition. The printing condition includes the printing parameters that determine the visual attributes of a print including the printing process, paper category, etc. The proper use of ICC profiles becomes difficult when the user cannot determine whether the paper to be used is similar to the paper that was used when making the ICC Profile.

10 Why paper categories are important to the process of print characterization David Q. McDowell 1

11 Fundamental Issues Print characterization provides relationship between CMYK input data and colorimetry of printed image (test target). Paper colorimetry locks one end of data space Paper characteristics determine maximum ink film thickness that can be supported. Paper characteristics impact solid ink color. Paper characteristics impact TVI. Profiles are based on characterization data but perform additional functions. 2

12 Ideal Approach Develop characterization data for every combination of: paper, ink set, screen ruling, screen type, solid ink density, etc. However, this is impractical (too many different papers)! 3

13 Real Color Management Need Given ICC profiles based on characterization data for inks matching an ISO 2846 criteria, specific SID aims, and a specific paper What other papers can these profiles be used with and achieve similar results? OR What paper characteristics can be measured that will predict consistency of characterization data (and profiles) between papers (these may be new measurements)? 4

14 Current measures No consistent categorization of paper in different parts of the world. General categories used by TC130 include: CIELAB General surface quality (coated, uncoated, etc.) Mass/unit area Industry measures Whiteness/Brightness Gloss Mass/unit area Coating type 5

15 General Questions How do we decide what would be helpful to measure? Who should/can develop appropriate tests? How can we decide if this whole approach is meaningful? Are there other approaches that will enable characterization data/profile portability between various printing papers. 6

16 Problems with current paper categories Paper categorisation meeting, Leeds 15th June 2006

17 Paper classification in ISO Classification is almost the same in 2004 version as with 1996 version Paper world has changed in last 10 years quite a much! Jouni Marttila

18 Traditional classification of printing paper grades as in early 90' VALUE (Traditional Price) Clear classification according to fibre content and surface properties Paper type 1&2 in ISO SC LWC Std MWC Paper type 3 in ISO WFC WFC Art Newsprint QUALITY (Brightness, Surface & Print Quality) Jouni Marttila

19 Classification of printing paper grades nowadays VALUE (Traditional Price) Paper grades overlap much more and optical and surface properties are more important that fibre content Std.NP SC (B, A, A+ etc) INP MFC LWC Std Paper type 1&2 in ISO ?? LWC Hi-Brite MWC Single coated WFC Double coated Paper type 3 in ISO ?? WFC Art QUALITY (Brightness, Surface & Print Quality) Jouni Marttila

20 Pain points in ISO paper classification Paper shades do they reflect reality nowadays? 2. Matte-coated what is meant with that? 3. Gloss does it have anything to do with CM? 4. Is grammage important from CM and standardization point of view? 5. Slightly yellowish uncoated papers very minor product group is it worth mentioning? Jouni Marttila

21 1. Paper shade and luminance case study 6 PT3 4 WFC MWC Hi-brite LWC Std LWC 2 MFC SC L* MFC PT3 Hi-brite LWC MWC PT1 WFC 91 PT Coated fine and MWC's SC Std LWC -6 Spektrolino D50, 2, white backing Jouni Marttila

22 2. Matte-coated Roughness - PPS 4,5 4 3,5 3 2,5 2 1,5 1 0,5 0 Matt Silk Matte-coated in the standard actually refers to silk grades (semi-matt) Difference between silk and glossy grades in much smaller than with "true" matt grades Glossy Paper gloss, % Jouni Marttila

23 3. Gloss Paper surface has different properties roughness porosity gloss From CM point of view important are properties that affect print density dot gain In both cases most important paper property is Ink demand, which is controlled mainly by roughness (with coated grades) partly by porosity (especially with uncoated grades) Jouni Marttila

24 Ink demand an example (publication papers) 4,5 4 3,5 matt 115 g Coated fine/mwc 80 g Coated fine/mwc 65g MWC/LWC 48-54g LWC 45-56g SC PPS-roughness 3 2,5 2 1,5 1 0,5 silk grades glossy grades 0 0,8 1 1,2 1,4 1,6 1,8 Ink amount for print density of 1.4, g/m² Jouni Marttila

25 Classifications shade vs ink demand UWF Ink demand (dot gain) increases SC Std LWC MFC Hi-brite LWC MWC WFC Paper shade and brightness Jouni Marttila

26 ECI/WOWG Web Offset Working Group under European Color Initiave Work started in 2004 by evaluating the usability of current ISO profiles in web offset printing It continued by developing new profiles for SC and MFC papers Chairman: Olof Druemmer Jouni Marttila

27 ECI/WOWG ICC profile naming ECI/Fogra will publish new set of characterisation data along with profiles in near future (autumn06?) WOWG made suggestion, which influences also to paper classification Profile naming Paper grade TAC Characterisation data ECI_ISO_Web_WFC Woodfree coated, Medium weight coated 320% Fogra xx (39?) same as in sheet-fed ECI_ISO_Web_LWC Light weight coated 300% Fogra xx (40?) same as in sheet-fed ECI_ISO_WEB_SC Supecalandered 270% Fogra xx created by WOWG ECI_ISO_Web_MFC Machine finished coated tba Fogra xx to be created by WOWG ECI_ISO_Web_NP Newsprint (in heatset) tba Fogra xx to be created by WOWG ECI_ISO_Web_WFU Woodfree uncoated tba Fogra xx Jouni Marttila

28 Summary Classification from CM point of view should be based on paper shade and brightness needs to be fine-tuned in future revisions of ISO dot gain (which can be predicted through ink demand) Clear categories can be found WFC/MWC LWC MFC SC UWF NP However there will always be papers on the borderline and decisions have to be made case by case Jouni Marttila

29 Paper Parameters That Affect Color Reproduction Danny C. Rich, Ph.D. Sun Chemical Color Research Laboratory

30 Why does my profile not match my customer s profile?

31 Types of Paper Paper Type is not a quality indicator or grade in paper classification. New raw materials are changing the meanings of some performance parameters. Paper type was devised by the National Recovery Act (NRA) in the 1930s Today it relates primarily to the Brightness of a paper and thus to the price of the paper.

32 Paper Tests There are many tests applied to papers. Many tests are related to end use or printability. In addition to paper appearance several parameters impact the appearance. Ink gloss Ink holdout Coating content Paper smoothness Refining & Calendering

33 Gloss: ISO 8254 Paper Gloss Ink Gloss

34 What is Happening to Publication Paper? Old New W/B W/B What is the difference between CIE Whiteness and Brightness?

35 Reflectance & Fluorescence Total Radiance Factor (%) APCO Copy InkJet Leneta Wavelength (nm)

36 ISO Whiteness & Brightness Brightness is the intrinsic reflectance factor measured with a reflectometer having the characteristics described in ISO 2469, equipped with a filter or corresponding function having an effective wavelength of 457 nm and a width at half height of 44 nm, and adjusted so that UV content of the illuminantion incident upon the test piece corresponds to that of CIE illuminant C. CIE whiteness is a measure of whiteness derived from CIE tristimulus values determined under the conditions specified in this International Standard and expressed as whiteness units. W = Y + W x (x n x) + W y (y n y) W x = 800, W y = 1700, x n = , y n = for CIE D65/10

37 ISO Brightness Re: Paper Optics Nil Pauler

38 Effect of FWA on Color Readings Measured CIELAB Color Differences (UVX-UVI) for ink-jet paper and an ink jet printer Halftone (%) Cyan Magenta Yellow Black

39 Extenders in Papers

40 Effect of Coating, Refining and Calendering

41 Paper Smoothness

42 3D Surface Profilometer Display of Gravure Dots on Packaging Film Gravure print - 3D image (angle view) of Polypropylene printed film

43 Single Gravure Dot on Polypropylene Packaging Film Gravure dot on PP film 3D image (angle view)

44 Optical Profilometer Images and Scans of Gravure Printing on Paper Substrate 3D image Photomicrograph Rough and wavy surface of paper skipped dots Rough and flat surface of paper no skipped dots

45 Cellulose fiber Valley Skipped dot Photomicrograph and 3D image (top view) of the same area of gravure print on paper.

46 Protruding cellulose fiber bump Missing dots leads to a mottled appearance and inconsistent reflectance readings over small areas. Valley Skipped dot Photomicrograph and 3D image (top view) of the same area of the gravure print on paper.

47 Initiatives to Improve Predictability of Printing IDEAlliance has formed a Print Predictability Paper Taskforce Part of Paper Supply Chain Committee Develop, deploy, and adopt processes and methodologies for the content and print creator (i.e., art director, designer, and product manager) and buyer that supports and enables color management technologies to be used for print predictability across the supply chain. Select and drive adoption of techniques, tools and methodologies enabling an advertiser, print creator or buyer, and printer to accurately evaluate print and proofing processes that reflect print predictability. Create a methodology, process or technique that is based on paper performance The paper s ability to reproduce imagery so that paper purchasers can evaluate their choices based on both optical and physical factors. Paper buyers, content creators and printers do not know how a paper will perform on press nor duplicate color prior to printing. Current paper classification is based on Brightness. Brightness does not correlate with critical performance properties.

48 IGT Printability Tests Offset Gravure Flexo Newsprint Mottle W-57 (1) W-82 (2) W Print penetration W-24 W-24 (3) W-24 (4) W-24 Set-off W W-48 Wet-pick/repellence W W-32 IGT Roughness W-28 W-28 W-28 W-28 Print through W-43 W-82 W-76 W-43 Gloss W-49 W-82 W-76 W-49 Ink transfer W-50 W-82 W-76 W-50 Picking ISO 3783 ISO 3783 ISO 3783 W-44 (linting)

49 IGT Printability Tests

50 The End Thanks to: W. degroot IGT Nils Pauler Paper Optics Mead Paper

51 Classification of papers for gravure and offset processes ICC ISO TC 130 joint meeting 2006_06_15 Leeds, UK Karl Michael Meinecke Bundesverband Druck und Medien German Printing and Media Industries Federation Paper Classification ICC ISO TC Leeds, UK 1

52 Classification of gravure papers 2006 Gravure printers (bvdm committee) and paper manufacturers jointly developed the classification of gravure publication papers Paper manufacturers allocated their products into the classification (coated and uncoated) ECI gravure working group (bvdm, ECI, ERA) adopted the classification, it is considered as applicable and complete Standard gravure printing conditions (HWC; LWC; SC; MF) are fitting well into classification Paper Classification ICC ISO TC Leeds, UK 2

53 Classification of gravure papers 2006 Uncoated papers Paper Classification ICC ISO TC Leeds, UK 3

54 Classification of gravure papers 2006 Coated papers Paper Classification ICC ISO TC Leeds, UK 4

55 Classification of gravure papers 2006 Documentation Classification of papers for gravure publication printing (8 pages document download 7 international paper manufacturers: Burgo, Holmen, Myllykoski, Norske Skog, SCA, Stora Enso, UPM 85 papers allocated to 11 categories Paper Classification ICC ISO TC Leeds, UK km@bvdm-online.de 5

56 Paper Classification ICC ISO TC Leeds, UK 6

57 Paper Classification ICC ISO TC Leeds, UK 7

58 Paper Classification ICC ISO TC Leeds, UK 8

59 Classification of papers for offset processes (proposal) 2006 Classification of papers for offset processes (sheet-fed, web-fed, continuous forms, newspaper printing) Integration of existing paper classes of ISO and ISO (PT 1 to 5, newsprint) 16 subcategories (to be reviewed), papers to be allocated by paper manufacturers Paper Classification ICC ISO TC Leeds, UK km@bvdm-online.de 9

60 Classification of offset papers - coated Paper Classification ICC ISO TC Leeds, UK km@bvdm-online.de 10

61 Paper Classification ICC ISO TC Leeds, UK 11

62 Classification of offset papers - uncoated Paper Classification ICC ISO TC Leeds, UK km@bvdm-online.de 12

63 Classification of gravure papers: uncoated bvdm/eci 2006 Paper Type standard appl. Paper Type long version Description ISO brightness Bulk [cm³/g] Product examples N-ST News Standard standard newsprint without gravure adaptation ,35 1,60 Holmen News N-P PSR_ECI_MF News Plus improved newsprint for gravure process ,35-1,50 Holmen Plus G68, Exopress, Flyopress DIR Directory uncoated wood content for directories ,25-1,50 Opalite G, Opalite 67 G Alfa (+) SC B SC B high content of recycled paper; online calandered ,85-0,95 UPM ECO, Envipress SC ST PSR_ECI_SC SC Standard super calandered magazine paper with low content of recycled paper ,85 UPM Max G, Publipress, GraphoGravure SC-P SC Plus opt. improved SC paper ,85-0,90 UPM cat, M-Plus, GraphoGrande SC-80 SC 80 highly opt. improved SC paper, partially semimatte ,85-0,94 UPM Lux 80, Innopress, GraphoPrestige application : PSR_ECI_LWC application : PSR_ECI_SC application : PSR_ECI_MF

64 Classification of gravure papers: coated bvdm/eci 2006 Paper Type standard appl. Paper Type long version Description ISO brightness Bulk [cm³/g] Product examples LWC-B LWC-St LWC P MWC-90 HWC-WF LWC B PSR_ECI_LWC LWC Standard LWC Plus PSR_ECI_HWC MWC 90 HWC woodfree light weight coated high wood content, film coating light weight coated catalogue or magazine paper; wood content LWC catalogue LWC magazine opt. improved coated magazine paper; wood content medium weight coated; double coated magazine paper; high content opt. brightener heavy weight coated 2-3 times coated offset paper high content opt. brightener; mainly for cover production 72 0,80 Ultra Mag RG >92 0,80 0,84 0,89 0,75 0,80 0,75-0,80 0,72 0,80 UPM Cote G, Bavaria Ultra, Turnopress Bavaria Classic, Neopress, UPM Cote G UPM Cote Plus Terrapress, UPM Ultra, MY Brite UPM Star, Novapress G Galerie fine, Royal Xpress, UPM Finesse application: PSR_ECI_LWC application: PSR_ECI_HWC

65 ICC Meeting Paper classification Leeds, 15/06/2006 A.S. Gombart R&D

66 Graphic Standard ISO and coated papers specifications

67 Agenda 1. Situation 2. Methodology 3. Results 1. Paper types 1&2 2. Paper type 3 R&D - Sappi Fine Paper Europe 3

68 1. Situation Feedback from printers: The standard is useful and presents on the long term clear advantages in terms of: process standardisation and improvement quality stability cost reduction, increased efficiency However, the practical implementation can be difficult because of: Spectrophotometer measurement Forecast of tone value increase per paper sort Paper shade difficult to sort papers by type large tolerance windows in a* and b* values many papers cannot be sorted into a type (high brightness, LWC, reels matt/silk ) R&D - Sappi Fine Paper Europe 4

69 1. Situation Paper specification ISO Source: ISO :2004(E) R&D - Sappi Fine Paper Europe 5

70 2. Methodology Papers corresponding to types 1, 2 and 3 have been selected from the market with common grammages. Type 1 & 2: coated sheets Type 3: coated reels The following measurements have been carried out: Measurement Paper gloss Paper shade Brightness Norm ISO :2003 ISO :2004 ISO 2470:1999 Specific Tappi 75 D50, 2 observer, 0/45 geometry, black backing Paper backing R&D - Sappi Fine Paper Europe 6

71 3.1. Paper types 1&2 Paper gloss TAPPI 75 Gloss paper types 1 and 2 WFC-Gloss WFC-Silk/Matt 90 Gloss (%) Type 1 Type 2 Actually 3 groups: Gloss Silk/dull Matt Gloss level is part of the specificity of the printed object and varies therefore a lot R&D - Sappi Fine Paper Europe 7

72 3.1. Paper types 1&2 Paper shade (1) a*, b* coordinates influence of backing 250g black backing 250g white backing 170g black backing 170g white backing 135g black backing 135g white backing 100g black backing 100g white backing -3,00 0,50 0,60 0,70 0,80 0,90 1,00 1,10 1,20 1,30 1,40 1,50 b* -3,50-4,00-4,50-5,00 Larger influence of black backing on low grammages related to opacity. -5,50-6,00-6,50-7,00 a* R&D - Sappi Fine Paper Europe 8

73 3.1. Paper types 1&2 Paper shade (2) a*, b* coordinates sheetfed papers - black backing Europe North America Asia 1,00 0,00-3,0-2,0-1,0 0,0 1,0 2,0 3,0-1,00-2,00-3,00 Many papers from the market are not or not well described by the norm. b* -4,00-5,00 Type 1/2: coated, wood-free -6,00-7,00-8,00-9,00 a* R&D - Sappi Fine Paper Europe 9

74 3.1. Paper types 1&2 Paper shade (3) a*, b* coordinates sheetfed papers - black backing Europe North America Asia 1,00 0,00-3,0-2,0-1,0 0,0 1,0 2,0 3,0 b* -1,00-2,00-3,00-4,00-5,00 No difference in shade between matt and gloss grades but 2 shade groups as function of the b* value. Type 1/2: coated, wood-free -6,00-7,00-8,00-9,00 a* R&D - Sappi Fine Paper Europe 10

75 3.1. Paper types 1&2 ISO Brightness ISO Brightness for paper types 1 & 2 Type 1 Type 2 100,0 99,0 98,0 97,0 ISO Brightness (%) 96,0 95,0 94,0 93,0 92,0 91,0 90,0 89,0 88,0 87,0 86,0 85,0 84,0 83,0 82,0 81,0 Same conclusions as for shade: 2 groups based on high or low b* value. 80, R&D - Sappi Fine Paper Europe 11

76 3.1. Paper types 1&2 ISO Brightness CIE w hiteness = f (b*) White backing 140 R 2 = 0, CIE whiteness (%) Whiteness is related to b* value: the higher the whiteness, the lower the b* value ,0-5,5-5,0-4,5-4,0-3,5-3,0-2,5-2,0 b* R&D - Sappi Fine Paper Europe 12

77 3.1. Paper types 1&2 conclusions Black backing has a huge influence on L*, a* and b* values, depending on grammage. The gloss values of glossy grades are higher than the values specified in the norm. The gloss values of Matt/Silk grades are lower than the values specified in the norm. A majority of the papers investigated are bluer and redder as the standard shade specifications. The majority of the papers investigated have a higher ISO Brightness as the one specified in the norm. Papers that have a higher Brightness usually have a lower b* value. R&D - Sappi Fine Paper Europe 13

78 3.2. Paper type 3 Paper gloss TAPPI 75 Gloss - Reels Gloss grades Silk/Matt grades Actually 3 groups: 65 Gloss (%) Type 2 Type 3 Gloss Silk/dull Matt Gloss level is part of the specificity of the printed object and varies therefore a lot R&D - Sappi Fine Paper Europe 14

79 3.2. Paper type 3 Paper shade a*, b* coordinates - gloss and matte-coated reelfed grades Europe North America Asia Type 3 6,00 5,00 4,00 3,00 2,00 1,00 b* 0,00-4,0-3,0-2,0-1,0 0,0 1,0 2,0 3,0 4,0-1,00-2,00-3,00-4,00 Type 1&2-5,00-6,00-7,00-8,00 a* R&D - Sappi Fine Paper Europe 15

80 3.2. Paper type 3 Paper shade a*, b* coordinates - gloss and matte-coated reelfed grades Europe North America Asia Type 3 6,00 5,00 4,00 b* 3,00 2,00 1,00 0,00-4,0-3,0-2,0-1,0 0,0 1,0 2,0 3,0 4,0-1,00-2,00-3,00 No difference in shade between matt and gloss grades but 2 shade groups as function of the b* value. -4,00 Type 1&2-5,00-6,00-7,00-8,00 a* R&D - Sappi Fine Paper Europe 16

81 3.2. Paper type 3 ISO Brightness ISO Brightness for paper type 3 Gloss reels Silk/Matt reels ISO Brightness (%) Brightness of commercial grades usually higher than norm specification R&D - Sappi Fine Paper Europe 17

82 3.2. Paper type 3 ISO Brightness ISO brightness = f(b*black backing) ISO Brightness (%) R 2 = Brightness is related to b* value: the higher the brightness, the lower the b* value ,0-7,0-6,0-5,0-4,0-3,0-2,0-1,0 0,0 1,0 2,0 b* R&D - Sappi Fine Paper Europe 18

83 3.2. Paper types 3 conclusions The shades for paper type 3 specified in the norm do not correspond very well to the shades found in the market for the papers measured. All investigated papers have a higher ISO brightness than the one specified in the norm. Papers with a higher Brightness usually have a lower b* value. R&D - Sappi Fine Paper Europe 19

84 4. Conclusions Paper shade: variation in b* is much higher than variation in a* value. b* values from market paper are usually low, related to market demand (high brightness, bluish shades). Paper gloss: gloss grades have very high TAPPI 75 gloss values. there is a lot of variation in the gloss values of matt/semi-matt/pearl papers. Paper differentiation as a function of wood content is difficult for coated grades because of effect of optical brighteners. Difference to be made as function of b* value or brightness. R&D - Sappi Fine Paper Europe 20

85 Thank you for your attention

86 White Point Compensation Paper, the Fifth Color Current Classifications Optical Brighteners By Trish Wales Sappi Fine Paper June 15, 2006

87 First Segmentation U.S. vs. EU Coated Supercalendered Newsprint Uncoated Coated Supercalendered Newsprint Uncoated

88 U.S. Coated Paper Classification Classification Brightness Classification Brightness [Tappi T452] [Tappi T452} Premium 94+ Premium N/A No. 1 Coated No. 1 Coated N/A No. 2 Coated No. 2 Coated 87+ No. 3 Coated No. 3 Coated No. 4 Coated No. 4 Coated No 5 Coated ] N/A No. 5 Coated Under 75 Coated Free Sheet Classification Coated Groundwood Classification

89 Supercalendered Classification SC-A++ SC-A+ SC-A SC-B SC-C GE Brightness > Gloss > low 50's High 40's - low 50's High 30's - low 40's Low 30's Low 30's or <

90 Uncoated Paper Classification Quality and Use Offset Utility Opaque Premium Opaque Copy Paper Text and cover Writing Papers Bristols Newsprint Finish Smooth Vellum Embossed Laid Wove

91 Brightness

92 Brightness Illuminant Ink Film Paper Brightness is measured at one wave length 457 nm

93 Test Methods Brightness TAPPI - Paper (GE Brightness) ISO - Paper Standard ID Geometry Illuminant TAPPI T452 Directional C ISO 2469, 2470 Diffuse D65 [C]

94 Test Comparison BRIGHTNESS Paper Grades ISO C ISO D65 TAPPI C

95 European Classification Related to paper manufacturing process Separated by fiber type Number of coating layers considered

96 European Papers Chemical Pulp Mechanical Pulp UWF Std WFC HWC MWC Art Relative Price Std. LWC FCO MFC SC Newsprint Relative Quality

97 ISO Five types Optical characterization Shade/Gloss

98 ISO Categories 1. Gloss Coated, woodfree 2. Matte Coated, woodfree 3. Gloss Coated, web 4. Uncoated, white 5. Uncoated, slightly yellowish

99 Paper Types +/-5 +/-2 +/-2 +/-2 +/-2 +/-3 +/-3 Toler ance 6/ / / / / Gloss/ ISO BRT b* White b* Black a* White a* Black L* White L* Black Type

100 Fluorescence

101 Optical Brighteners Prevalent Increasing Visual Matching challenge

102 What are they? Chemical additives Textiles Paints Paper

103 Paper OBA Properties Absorb light in UV More UV, more absorbed, more emitted Emit in blue region No UV, no emission Unstable in light Paper goes from white to yellow

104 Optical Brighteners Re-Emission Absorption Wavelength in nm -100

105 OBA affects Print See effect in the white spaces See effect through cyan ink Effect blocked by magenta and black ink Yellow ink effect depends on ink transparency On-line measurements give false reading Pulsed Xenon White point compensation

106 Useful Information Paper OBA s behave in optically similar ways Level of OBA s range from 2 to 8 Measured by Brightness with UV included or excluded Response is linear Level of UV in illuminant is critical

107 Paper Impacts Profiles Increasing gloss, saturated tone gamut expansion Increasing L*, highlight tone gamut expansion

108 Paper categorisation meeting Leeds, June Current activities in ISO/TC6/WG3 Paper, board and pulps-optical properties Nils Pauler, M-real ISO/TC6/WG3

109 Liaison ISO/TC6/WG3 with other organisation Convenor Dr Byron Jordan Liaison with CIE Dr Joanne Zwinkel Liaison with ISO/TC130 Graphic Arts Mr Bryan Sunderland Liaison with ISO/TC38-Textiles Mr Richard Harold Liaison with ICC Mr Nils Pauler Nils Pauler, M-real ISO/TC6/WG3

110 Activities in paper industry related to colour Increased focus on shade of papers Measurements and Simulations of L*a*b* of paper products A transition from black & white printing to four colour printing in office sector Colour management of traditional print Evaluation of colour reproduction of desktop printers ICC profiles for RGB printers Simulation of optical interaction between ink and paper. (Co-operation with Universities) Nils Pauler, M-real ISO/TC6/WG3

111 Optical instruments used in paper industry D/ 0 Spectrophotometers (L&W Elrepho, Elrepho SF450, ) Gloss instrument 45/0 Spectrophotometers (Gretag Macbeth Spectrolino) Scanner calibrated for L*a*b* measurements Nils Pauler, M-real ISO/TC6/WG3

112 International standards for reflectance measurements ISO 2469 Measurement of diffuse radiance (reflectance) factor ISO 2470 Measurement of diffuse blue reflectance factor (ISO brightness) ISO 2471 Determination of opacity (paper packing) diffuse reflectance method ISO Determination of CIE whiteness, D65/10 (outdoor daylight) ISO Determination of CIE whiteness, C/2 (indoor lighting) ISO 5631 Determination of Colour (L*a*b*), C/2 ISO 9416 Determination of light scattering and absorption coefficient using Kubelka-Munk theory Nils Pauler, M-real ISO/TC6/WG3

113 ISO methods for reflectance measurements new ISO numbers and new methods ISO 2469 Diffuse reflectance ISO ISO Brightness, (UV(C)) ISO D65 Brightness, (UV(D65)) ISO 2471 Opacity ISO Colour, L*a*b*, C/ 2 ISO Colour, L*a*b*, D65/10 ISO Colour, L*a*b*, D50/2 ISO 9416 Kubelka-Munk coefficients ISO CIE-whiteness (D65/10 ISO Indoor- whiteness (C/2 ) ISO Transmittance Nils Pauler, M-real ISO/TC6/WG3

114 ISO methods paper and board Gloss measurements ISO Gloss at 75, Tappi ISO Gloss at 75, DIN ISO Gloss at 20, TAPPI Nils Pauler, M-real ISO/TC6/WG3

115 The calibration hierarchy for absolute reflectance measurements Perfect reflecting diffuser Standardizing Laboratories (NRC, NIST, PTB) Authorized Laboratories (CTP, KCL, Paprican, STFI-P,TLS) Reflectance instruments D/0 ISO 2469 All the larger Pulp and Paper companies rely on ISO calibration! Nils Pauler, M-real ISO/TC6/WG3

116 ISO diffuse reflectance Optical geometry D/0 Optical sphere with diameter 150 mm Measure area with a diameter of 28 mm Illumination area with a diameter of 34 mm Gloss trap Variable UV filter Three UV settings: UV(D65), UV(C) and UVex(420) Nils Pauler, M-real ISO/TC6/WG3

117 Instrument according to ISO Roo UVexl UV(C) UV(D65) Wavelenght,nm R oo Gloss trap UV Cut off filter R o UV - trim filter Nils Pauler, M-real ISO/TC6/WG3

118 Calibration of spectral reflectance factors Nils Pauler, M-real ISO/TC6/WG3

119 Calibration of the UV content in the illumination; UV(D65) and UV(C) Nils Pauler, M-real ISO/TC6/WG3

120 Radiance factor of a calibrated copy paper Roo Wavelenght,nm UVexl UV(C) UV(D65) Differences between instruments 0,2-0,5%! Nils Pauler, M-real ISO/TC6/WG3

121 The new Colour measurement method ISO CD Colour, L*a*b*, D50/2 (Draft) Instrument: ISO 2469 Light source: Calculation: Fluorescence as standard illumination C L*a*b*, D50/2 Nils Pauler, M-real ISO/TC6/WG3

122 L&W Elrepho vs. Spectrolino Instrument L&W Elrepho Spectrolino Optical geometry D/0 with 45 /0 Illumination Xenon lamp Tungsten lamp A light UV adjustment UV(C), UV(D65), UVexcl ~UV(C), ~UV(D65), UVexcl Measuring area Diameter: 28 mm 4 mm Illumination area Diameter: 34 mm? mm Gloss trap Black annulus around 45 /0 the receptor aperture 45 /0 + pol. filter Opaque pad R over black or white background Nils Pauler, M-real ISO/TC6/WG3

123 Summary Is there a need for common optical measurement methods? Will colour properties of paper be used in colour management? Should absolute calibration be a common goal? Is this a way to involve paper industry in future media standards? Will it improve the communication between paper and graphical industry? Can we use the instruments of today? Is the new L*a*b* D50/2, UV(C) comparable to methods used in graphical arts? Can we use L*a*b* D65, UV(D65) for office papers? Is the gloss trap of ISO 2469 D/0 comparable to 45 /0 instruments? Will new Spectral Scanners and/or Digital Cameras be the future? A workshop is planned in Sweden autumn 2006 Nils Pauler, M-real ISO/TC6/WG3

124 POSITION PAPER Revised Print Predictability Paper Taskforce 5/24/06 IDEAlliance Policy : Antitrust Statement As associations of competitors, trade associations must be vigilant to ensure that state and federal antitrust laws are respected. The general improvement of the industry benefits the public. This is why Congress granted the privilege of tax-exempt status to trade associations. Our focus must be the general improvement of our industry. We must refrain from actions, which either may suppress competition among members or give members a competitive advantage over nonmembers. IDEAlliance has formed a Print Predictability Paper Taskforce working with its Print Properties and Print Media Supply Chain Committees to develop, deploy, and adopt processes and methodologies for the content and print creator (i.e., art director, designer, and product manager) and buyer that supports and enables color management technologies to be used for print predictability across the supply chain. Scope Select and drive adoption of techniques, tools and methodologies enabling an advertiser, print creator or buyer, and printer to accurately evaluate print and proofing processes that reflect print predictability. The intent of this initiative is NOT to change paper categories, characterization, or measurement or the way this information is currently communicated. Purpose The printing process has advanced in recent years, controlling input variables and delivering more consistent product to print buyers. CTP, closed loop ink systems and on line measurements are a few examples. Color management and unified work flows are current technological advances. Input variables must be measured and controlled for new technologies to succeed. The purpose of this effort is to create a methodology, process or technique that is based on paper performance in the printing system and paper s ability to reproduce imagery so that paper purchasers can evaluate their choices based on both optical and physical factors. Paper buyers, content creators and printers do not know how a paper will perform on press nor duplicate color prior to printing. Current paper classification is based on Brightness, a measurement never intended to be a predictor of paper quality. Brightness does not correlate with critical performance properties. Further, the globalization of the IDEAlliance Position Paper