ISO/TS 19857:2021

TECHNICAL ISO/TS
SPECIFICATION 19857
First edition
2021-06
Paper, board and printing inks –
Printability – Laboratory test method
for offset ink setting
Papier, carton et encres d'impression – Imprimabilité – Méthode
d'essai de laboratoire pour le séchage de l'encre offset
Reference number
©
ISO 2021
© ISO 2021
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ii © ISO 2021 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Apparatus and materials. 2
4.1 Printing device . 2
4.2 Inking device . 3
4.3 Printing formes . 3
4.4 Ink pipette . 4
4.5 Packing . 4
4.6 Substrate carrier . 4
4.7 Analytical balance. 4
4.8 Timer . 4
4.9 Densitometer . 4
4.10 Test paper . 5
4.11 Reference counter test strips . 5
4.12 Setting test ink . 5
4.13 Cleaning . 5
5 Test method . 5
5.1 Principle . 5
5.2 Test conditions . 5
5.2.1 Climatic conditions . 5
5.2.2 Settings of the printability tester . 6
5.2.3 Settings for the inking unit . 6
6 Procedure. 7
6.1 Preparation . 7
6.2 Preparational test for ink transfer determination. 7
6.3 Test execution on different instruments . 7
6.3.1 IGT-type testers . 7
6.3.2 Prüfbau-type testers . 8
7 Assessment . 9
8 Reporting .10
Annex A (informative) Checking the printing device and the inking device .11
Annex B (informative) Visualization of defects of used materials.12
Bibliography .22
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
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electrotechnical standardization.
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described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
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iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 6, Paper, board and pulps, Subcommittee
SC 2, Test methods and quality specifications for paper and board.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2021 – All rights reserved

Introduction
This document describes a test method to evaluate the ink setting characteristics of a specific ink/
substrate combination in offset lithographic printing.
Set-off is the transfer of ink from the front of one sheet to the back or the front of the next sheet.
Setting is the process of penetration of liquid ink components of low viscosity into the penetrable
substrate. These low-viscosity liquids within the ink are mineral oils, vegetable oils or esters of
vegetable oils. By separation from those low-viscous liquids, the remaining ink film solidifies. This is
combined with a varying change in the surface tack depending on the inks-varnish system and the
time. The surface tack usually increases at the begin of the setting and later-on drops to zero. Setting
is either the main drying mechanism for ink systems (e.g. news inks) or part of a multi-channel drying
mechanism (e.g. conventional sheet fed offset inks or heatset inks). The laboratory test for setting
performs a set-off print of the fresh print to a non-printed substrate at defined times. The ink transfer
to the non-printed substrate not only depends on the degree of solidification of the ink by setting, but
also on the actual level of tack of the original ink film. Thus, the test result is a combined measure.
The absorption properties of the paper are of great influence in offset lithography printing.
Inappropriate absorption can lead to numerous printing problems such as ink set-off, bad adhesion,
mottling, unpredictable tone value increase, poor rub resistance, damaging of first printed side on
perfecting presses after perfecting and others.
The more absorbent the paper is, the less time will be needed for the ink to set sufficiently for further
processing, but other properties can be affected adversely by fast ink setting. Very short times should
be used when testing the processing of wet sheets, e.g. in a perfector press. Longer times are used for
paper handling right after printing, and very long times are used for further processing such as folding
and cutting.
Depending on the purpose of the test, there are three options for the paper-ink combination:
— Reference ink on production paper;
— Production ink on reference paper;
— Production ink on production paper, which can be divided into the following, depending on the
application of the print:
— Set-off face-to-face (e.g. set-off after folding);
— Set-off face to back (e.g. set-off in a stack of paper).
TECHNICAL SPECIFICATION ISO/TS 19857:2021(E)
Paper, board and printing inks – Printability – Laboratory
test method for offset ink setting
1 Scope
1) 2)
This document describes a laboratory test method, using an IGT -type or a prüfbau -type printability
tester, for the preparation of specimens to evaluate the absorption rate of an ink on a substrate in offset
lithography by setting-off the printed surface to an unprinted surface.
This method describes testing with an amount of ink simulating either single colour or multi-colour
printing. The print and the set-off print (counter print) are made with interval times, between print and
set-off, common for the target process.
This method evaluates a particular ink and substrate combination.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 5-4, Photography and graphic technology — Density measurements — Part 4: Geometric conditions for
reflection density
ISO 2834-1, Graphic technology — Laboratory preparation of test prints — Part 1: Paste inks
ISO 2846-1, Graphic technology — Colour and transparency of printing ink sets for four-colour printing —
Part 1: Sheet-fed and heat-se
...