introduction
ISO (International Organization for Standardization) is a global alliance of national standards bodies (ISO member bodies). The development of international standards is usually carried out through ISO technical committees. Each member institution interested in a subject on which a technical committee has been established has the right to be represented on that committee. International governmental and non-governmental organizations liaising with ISO are also involved in this work. ISO works closely with the International Electrotechnical Commission (IEC) on all matters of electrical standardization.
International standards are drafted in accordance with the rules given in Part 2 of the ISO/IEC Directive.
The main task of the technical committee is to develop international standards. The draft international standard adopted by the Technical Committee will be circulated to the member bodies for voting. Publication as an international standard requires approval by at least 75% of member institutions.
Please note that certain elements of this document may be subject to patent rights. ISO is not responsible for identifying any or all such patents.
ISO 2846-2 was developed by the Technical Committee ISO/TC 130, Graphic Technology.
ISO 2846-2-2017 Printing technology – Colour and transparency of four-colour printing inks – Part 2: cold-set offset lithography
The second edition cancels and replaces the first edition (ISO 2846-2:2000), in which articles 4 and 5 have been technically revised and the colorimetric characteristics of the inks have been adjusted to meet the actual commercial requirements and process standard ISO 12647-3[1]. The details of test print preparation specified in ISO 2834-1 have now been removed.
ISO 2846 consists of the following sections under the general heading Graphics Technology – Color and transparency of printing ink groups for four-colour printing:
– Part 1: Sheet-fed and heat-set web offset lithography
– Part 2: Cold-set offset lithography
– Part 3: Intaglio printing of publications
– Part 4: Screen printing
– Part 5: Flexographic printing
ISO 2846-2-2017 Printing technology – Colour and transparency of four-colour printing inks – Part 2: cold-set offset lithography
introduce
The first draft of ISO 2846-2 was written by ISO/TC 130 for material and process control. They examined the colorimetric properties of commercial cold-set web offset inks from around the world and found a set of color coordinates that adequately represented these color coordinates within reasonable tolerances. Since the first publication of this part of ISO 2846, additional coordination between the various national bodies involved in ISO/TC 130 has shown that some small improvements to the contrast color target will bring it more in line with the practical commercial printing requirements and process standard ISO 12647-3 [1].
This part of ISO 2846 will allow printers to obtain sets of printing inks from a variety of sources that will produce similar colors when printed on a reference substrate at the appropriate film thickness. This will allow the color separation of cold-set offset printing to be based on known color standards. The colorimetric properties specified in this part of ISO 2846 can only be obtained when the ink is printed on the reference substrate. However, the similarity of the two inks on the reference substrate will ensure the similarity on the other substrate.
1 Range
This part of ISO 2846 specifies the color and transparency of inks for four-color cold-set web offset printing when printed on a printability tester under specified conditions. It also describes testing methods to ensure consistency.
This part of ISO 2846 does not apply to fluorescent inks and does not specify pigments (or spectral reflectance) so as not to rule out future use of suitable pigment combinations and still claim to meet its colorimetric requirements.
ISO 2846-2-2017 Printing technology – Colour and transparency of four-colour printing inks – Part 2: cold-set offset lithography
2 Normative references
The following reference files are difficult or lacking for the use of this document. For dated references, only the cited version applies. For undated references, a new version of the reference (including any revisions) applies.
ISO 536, paper and board – Determination of gram weight
ISO 2471, Paper and board – Determination of opacity (paper backing) – Diffuse reflection method
ISO 2834-1, Graphic techniques – Laboratory preparation of test prints – Part 1: Adhesive inks
ISO 8791-4, Paper and board – Determination of roughness/smoothness (leak method) – Part 4: print-surfing method
ISO 13655, Graphic Techniques – Spectral measurement and chrominance calculation of graphic art images
ANSI/ CGATS.5:2003, Graphic Techniques – Spectral measurement and chromaticity calculation of graphic art images
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1 Cold set printing
Web offset printing without accelerated drying
Note 1: The ink collection is absorbed into the substrate.
3.2 Standard Ink
Inks for four-colour printing, when printed on a reference substrate and within the applicable ink film thickness range, comply with the colorimetric and transparency specifications in this part of ISO 2846
ISO 2846-2-2017 Printing technology – Colour and transparency of four-colour printing inks – Part 2: cold-set offset lithography
3.3 Primary Colors
The color of individual prints with yellow, magenta and cyan inks
Note 1: If prints are produced in accordance with this part of ISO 2846 and comply with specified colorimetric characteristics, they are standard primary colors.
3.4 Transparency
The ability of an ink film to transmit light is usually expressed as some measure of unwanted scattering
3.5 Transparency measurement T
The inverse of the slope of the regression line between the film thickness and color difference of the overprint of color ink on black
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