SIST ISO 24487:2024

INTERNATIONAL ISO
STANDARD 24487
First edition
2023-12
Graphic technology — Processless
lithographic plates — Evaluation
methods for characteristics and
performance
Technologie graphique — Plaques lithographiques sans traitement —
Méthodes d'évaluation des caractéristiques et des performances
Reference number
© ISO 2023
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ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Test procedure .2
4.1 General . 2
4.2 Test environment . 2
4.3 Plate imaging . 3
4.3.1 General . 3
4.3.2 Colour test form . 3
4.3.3 Abrasion and scratch resistance test form . 4
4.3.4 Image visibility test form . 5
4.4 Pre-dampening amount . . 6
4.5 Pre-inking amount . 6
4.6 Ink selection . 6
4.7 Substrate selection. 7
4.8 Fountain solution . 7
4.9 Press preparation and control . 7
4.9.1 Press preparation print run . 7
4.9.2 Reference printing aim values . 8
4.10 Printing method . 8
4.11 Plate exposure to light . 8
5 Assessment methods . 8
5.1 General . 8
5.2 On-press development . 9
5.2.1 Number of sheets required for on-press development . 9
5.2.2 Assessment of non-image area. 9
5.2.3 Assessment of solid area . 10
5.2.4 Assessment of intermediate tones. 11
5.3 Abrasion resistance . . . 11
5.4 Scratch resistance . 11
5.5 Resistance to toning .13
5.6 Chemical resistance .15
5.6.1 General .15
5.6.2 Rub test . 16
5.6.3 Drop test . 16
5.7 Plate performance for stop and restart . 16
5.8 Image visibility . 17
5.9 Run length . 17
6 Reporting requirements .19
Annex A (informative) Examples of measurement method and results .20
Annex B (informative) Example of evaluation results and classification .34
Annex C (informative) Examples of quality grade reporting .36
Bibliography .39
iii
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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ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
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 document 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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www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 130, Graphic technology.
This first edition of ISO 24487 cancels and replaces ISO 24487-1:2021, which has been technically
revised.
The main changes are as follows:
— the title and ISO number have been changed to remove the part number;
— the scope has been expanded to include evaluation points both specific to processless indicator and
those common to the conventional indicator:
— scratch resistance (see 5.4, A.7 and C.3);
— image visibility (see 5.8, A.8 and C.7);
— run length (see 5.9, A.9 and C.8)
— new terms have been added to Clause 3.
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
Introduction
Processless plates represent a simple way to prepare plates in prepress. Once a plate has been imaged,
it is mounted directly on the press where the plate coating is removed on start-up of the press. This
approach eliminates the plate processor, associated chemistry, energy required to power the processor,
water, and waste from plate preparation.
Perceived benefits of processless plates include ease of use and improved speed of production compared
to traditional plate preparation systems since there is no need for a plate processor or finishing unit.
Processless plates are mounted directly on press once imaged. Since costs associated with processors
and finishing units, including developer and cleaning solution, time and labour are eliminated, printing
using processless plates is perceived as a low-cost method.
The unique characteristic of processless plates is on-press development. After the exposure process
by computer to plate (CTP) exposing equipment, the non-image area of the photosensitive layer is
physically removed along with the ink and the fountain solution of the press.
The removal procedure is as follows.
— When the press is started, fountain solution and ink are applied. The fountain solution permeates
the unexposed (non-image) area of the photosensitive layer. The unexposed photosensitive layer is
then peeled from the base material by the tack of the printing ink.
— This peeled photosensitive layer is finely dispersed into the ink which is discharged on paper from
the press in the usual way. Parts of the peeled layer are also discharged into the fountain solution.
This document specifies evaluation methods for lithographic plate characteristics, on press development
performance, usability and print image quality. These evaluation methods are primarily intended for
processless lithographic plates but some can be used for the evaluation of all classes of lithographic
plate, however, it should be noted th
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