1、BRITISH STANDARDBS ISO 2846-2:2007Graphic technology Colour and transparency of printing ink sets for four-colour printing Part 2: Coldset offset lithographic printingICS 87.080g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54
2、g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS ISO 2846-2:2007This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 January 2008 BSI 2008ISBN 978 0 580 55003 4National forewordThis British Standard is the UK impl
3、ementation of ISO 2846-2:2007. It supersedes BS ISO 2846-2:2000 which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee PAI/43, Graphic technology.A list of organizations represented on this committee can be obtained on request to its secretary.This publicatio
4、n does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations. Amendments/corrigenda issued since publicationDate CommentsReference numberISO 2846-2:2007(E)I
5、NTERNATIONAL STANDARD ISO2846-2Second edition2007-12-15Graphic technology Colour and transparency of printing ink sets for four-colour printing Part 2: Coldset offset lithographic printing Technologie graphique Couleur et transparence des gammes dencre dimpression en quadrichromie Partie 2: Impressi
6、on lithographique offset rotatif coldset BS ISO 2846-2:2007ii iiiContents Page Foreword iv Introduction v 1 Scope 1 2 Normative references 1 3 Terms and definitions .1 4 Test method2 4.1 Principle2 4.2 Test print preparation2 5 Requirements for colour, transparency and ink film thickness range.3 5.1
7、 Colour .3 5.2 Transparency characteristics.4 5.3 Ink film thickness range4 Annex A (normative) Reference substrate .5 Annex B (informative) Detailed explanation of testing including examples .6 Annex C (informative) Spectral data9 Bibliography 11 BS ISO 2846-2:2007iv Foreword ISO (the International
8、 Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been est
9、ablished has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardiz
10、ation. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voti
11、ng. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such
12、 patent rights. ISO 2846-2 was prepared by Technical Committee ISO/TC 130, Graphic technology. This second edition cancels and replaces the first edition (ISO 2846-2:2000), of which Clauses 4 and 5 have been technically revised and the colorimetric properties of the inks were adjusted to be compatib
13、le with actual commercial requirements and to the process standard ISO 12647-31. Details for test print preparation, which are now specified in ISO 2834-1, have been deleted. ISO 2846 consists of the following parts, under the general title Graphic technology Colour and transparency of printing ink
14、sets for four-colour printing: Part 1: Sheet-fed and heat-set web offset lithographic printing Part 2: Coldset offset lithographic printing Part 3: Publication gravure printing Part 4: Screen printing Part 5: Flexographic printing BS ISO 2846-2:2007vIntroduction The initial draft of ISO 2846-2 was p
15、repared by ISO/TC 130 for materials and process control. They examined the colorimetric properties of commercial coldset web offset inks from around the world and found that a single set of colour coordinates could adequately represent these, within reasonable tolerances. Since the initial publicati
16、on of this part of ISO 2846, additional coordination between the various national bodies participating in ISO/TC 130 has suggested that some minor refinements of the colorimetric aims would make them more compatible with actual commercial printing requirements and to the process standard ISO 12647-3
17、 1. This part of ISO 2846 will allow printers to obtain sets of process inks from various sources which will produce a similar colour when printed on the reference substrate at the appropriate film thickness. This will allow colour separations for coldset web offset printing to be based on known col
18、our standards. The colorimetric characteristics specified in this part of ISO 2846 may only be obtained when the inks are printed on the reference substrate. However, similarity of two inks on the reference substrate will ensure similarity on another substrate. BS ISO 2846-2:2007blank1Graphic techno
19、logy Colour and transparency of printing ink sets for four-colour printing Part 2: Coldset offset lithographic printing 1 Scope This part of ISO 2846 specifies the colour and transparency to be produced by inks intended for four-colour coldset web offset printing when printed under specified conditi
20、ons on a printability tester. It also describes the test method to ensure conformance. This part of ISO 2846 is not applicable to fluorescent inks and does not specify pigments (or spectral reflectance) so as not to preclude the use of future suitable pigment combinations and still claim compliance
21、with its colorimetric requirements. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments)
22、 applies. ISO 536, Paper and board Determination of grammage ISO 2471, Paper and board Determination of opacity (paper backing) Diffuse reflectance method ISO 2834-1, Graphic technology Laboratory preparation of test prints Part 1: Paste inks ISO 8791-4, Paper and board Determination of roughness/sm
23、oothness (air leak methods) Part 4: Print-surf method ISO 13655, Graphic technology Spectral measurement and colorimetric computation for graphic arts images ANSI/CGATS.5:2003, Graphic technology Spectral measurement and colorimetric computation for graphic arts images 3 Terms and definitions For th
24、e purposes of this document, the following terms and definitions apply. 3.1 coldset printing web offset printing without accelerated drying NOTE Ink sets by absorption into the substrate. BS ISO 2846-2:20072 3.2 standard ink ink, intended for four-colour printing, which, when printed on the referenc
25、e substrate and within the applicable range of ink film thicknesses, complies to the colorimetric and transparency specifications of this part of ISO 2846 3.3 primary colours colours of individual prints from yellow, magenta and cyan inks NOTE If the prints are produced as specified in this part of
26、ISO 2846 and conform to the colorimetric characteristics specified, they are standard primary colours. 3.4 transparency ability of an ink film to transmit light, generally expressed as some measure of the unwanted scattering 3.5 transparency measurement value T reciprocal of the slope of the regress
27、ion line between ink film thickness and colour difference for overprints of chromatic inks over black 4 Test method 4.1 Principle Each ink is printed on the reference substrate described in Annex A at a range of ink film thicknesses. The colours which result are measured colorimetrically. Transparen
28、cy is evaluated by printing each of the three primary colours on a black substrate at a range of film thicknesses. The CIELAB colour difference is determined for each sample, between the printed and unprinted black, and the linear regression coefficient (slope of the regression line) between ink fil
29、m thickness and colour difference is calculated for each colour. For a detailed description of procedures, together with examples, see the informative Annex B. 4.2 Test print preparation 4.2.1 Prints for colorimetric evaluation For each of the inks to be evaluated, a number of test prints shall be m
30、ade using a printability tester, each produced at a different ink film thickness in accordance with the conditions specified in ISO 2834-1. They shall be made on the reference substrate as specified in Annex A. The sample material shall be kept in the dark under standard conditions of 23 C and 50 %
31、RH. The range of ink film thicknesses produced shall encompass that specified in 5.3. In cases where the approximate ink film thickness is known to result in the closest match of the target colorimetric values, a minimum of three prints shall be made. Otherwise, a minimum number of five prints shoul
32、d be made covering the full range of specified film thicknesses. 4.2.2 Prints for transparency evaluation Test prints for transparency evaluation shall be produced by printing the inks to be tested on a black substrate using a printability tester. Measurements of the CIELAB values of the black subst
33、rate shall be made prior to overprinting. The black shall have a lightness (L*) less than 30 when determined in accordance with ISO 13655. BS ISO 2846-2:20073The ink to be tested shall then be printed on the black substrate1)in accordance with the conditions specified in ISO 2834-1, such that a rang
34、e of samples, each with a different ink film thickness, is achieved. The range should approximate that defined in 5.3. 4.2.3 Setting of test prints Prior to colour measurement, all printed samples shall be left for at least 12 h to enable setting of the ink. 4.2.4 Colour measurement procedure Test p
35、rints shall be measured in accordance with ISO 13655 with the exception that a white backing, in accordance with ANSI/CGATS.5:2003, shall be used. NOTE 1 The requirements for white backing given in ANSI/CGATS.5:2003 are consistent with the future revision of ISO 13655. NOTE 2 The colorimetric values
36、 are related to the measurement procedure specified in ISO 13655. This means that the samples are measured spectrally, with a 0:45 (0:45 indicates the relationship between incident light and reflected light measurement angles) or 45:0 geometry instrument. For the calculation of CIELAB values and for
37、 the colour difference, the CIE 1931 (2) standard colorimetric observer data are used together with CIE standard illuminant D50. 5 Requirements for colour, transparency and ink film thickness range 5.1 Colour For an ink to conform to this part of ISO 2846, it shall meet the following requirements: a
38、) when printed as specified in 4.2.1, at some ink film thickness within the range specified in 5.3, the ink shall meet the colorimetric target value and tolerance specified in Table 1; b) it shall meet the transparency requirements specified in 5.2. NOTE Typical spectral data for inks conforming to
39、this part of ISO 2846 are provided in Annex C. Table 1 Colorimetric values CIELAB values Tolerances Ink L* a* b* *abE L* a* b* Yellow 80,4 (78,0) 1,4 (3,0) 61,6 (58,0) 4,0 (4,0) Magenta 55,5 (54,0) 47,6 (44,0) 0,7 (2,0) 4,0 (4,0) Cyan 59,1 (57,0) 23,9 (23,0) 27,1 (27,0) 4,0 (4,0) Black 36,8 (36,0) 1
40、,5 (1,0) 4,5 (4,0) u 36,8a(u 36,0a) 1,0 ( 1,0) 2,0 ( 2,0) Values in brackets pertain to measurement on black backing in accordance with ISO 13655 and are given for information only. aThis means that for black there is no symmetrical tolerance for L* but an upper limit.1) Contact the ISO/TC 130 Secre
41、tariat (DIN) for the source of a suitable substrate. BS ISO 2846-2:20074 5.2 Transparency characteristics To meet the specification for transparency an ink shall produce a value greater than that specified in Table 2 when determined by the principles and procedures outlined in 4.1 and 4.2.2. Table 2
42、 Transparency Ink colour Transparency measurement valueT Yellow 0,1 Magenta 0,2 Cyan 0,3 NOTE For highly transparent inks (usually cyan), the slope of the regression line may be zero or negative. In such a situation, the transparency measurement value is considered to be approaching infinity and the
43、refore the ink meets the specification. For further information concerning transparency evaluation, see B.2. 5.3 Ink film thickness range The range of ink film thickness, within which a standard ink for coldset lithographic printing shall conform to the colorimetric values specified in 5.1, is 0,7 m
44、 to 1,3 m. BS ISO 2846-2:20075Annex A (normative) Reference substrate The characteristics of the reference substrate shall be the following. a) Colour The colour values for the reference substrate are given based on white backing. In addition, black backing values are given for information. white ba
45、cking black backing CIELAB values L* = 85,2 4,0 L* = 82,0 4,0 a* = 0,9 2,0 a* = 0,0 2,0 b* = 5,2 2,0 b* = 3,0 2,0 Method: ISO 13655 (0:45, D50, 2, with the exception that white backing shall be used, as described in 4.2.4). b) Mass per area Specification: (48,8 2) g/m2Method: ISO 536 c) Opacity Spec
46、ification: 94 % Method: ISO 2471 d) Roughness Specification: (3,4 0,2) m at a pressure of 1 MPa Method: ISO 8791-4 BS ISO 2846-2:20076 Annex B (informative) Detailed explanation of testing including examples B.1 Colorimetric verification In order to evaluate whether an ink complies with this part of
47、 ISO 2846, it is necessary to print a number of samples, each of known ink film thickness, which adequately represent the range of ink film thicknesses specified in 5.3. These samples may be prepared on a printability tester by running up a small quantity of ink on the inking system, weighing the pr
48、inting forme prior to printing and then printing the test sample on the reference substrate. The printing forme is then re-weighed and the difference recorded. If the mass density of the ink is known (which may be determined by weighing a known volume of ink) and the printed area is measured, it is
49、possible to calculate the ink film thickness applied to the paper from the difference in mass before and after printing. The ink film thickness, s, may be calculated using the following equation: msA=where m is the difference in mass of the forme before and after printing; is the mass density of the ink; A is the area printed. After the inking unit has been cleaned, a slightly different amount of ink to that used the first time should then be applied to the inking system and the procedur
