ISO/DIS 24487-1

Graphic technology -- Processless plates

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DRAFT INTERNATIONAL STANDARD
ISO/DIS 24487-1
ISO/TC 130 Secretariat: SAC
Voting begins on: Voting terminates on:
2021-02-03 2021-04-28
Graphic technology — Processless plates —
Part 1:
Evaluation methods for characteristics and performance
ICS: 37.100.10
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
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ISO/DIS 24487-1:2021(E)
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PROVIDE SUPPORTING DOCUMENTATION. ISO 2021
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ISO/DIS 24487-1:2021(E)
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© ISO 2021

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ISO/DIS 24487-1:2021(E)
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 ............................................................................................................................................................................................ 2

4.4 Pre-dampening amount .................................................................................................................................................................. 4

4.5 Pre-inking amount ............................................................................................................................................................................... 4

4.6 Ink selection .............................................................................................................................................................................................. 4

4.7 Substrate selection .............................................................................................................................................................................. 4

4.8 Fountain solution .................................................................................................................................................................................. 4

4.9 Press preparation and control ................................................................................................................................................... 4

4.9.1 Reference printing aim values .............................................................................................................................. 5

4.10 Printing method ..................................................................................................................................................................................... 5

4.11 Plate exposure to light ...................................................................................................................................................................... 5

5 Assessment methods ........................................................................................................................................................................................ 6

5.1 General ........................................................................................................................................................................................................... 6

5.2 On-press development ..................................................................................................................................................................... 6

5.2.1 Number of sheets required for on-press development .................................................................. 6

5.2.2 Assessment of non-image area ............................................................................................................................ 7

5.2.3 Assessment of solid area ........................................................................................................................................... 8

5.2.4 Assessment of intermediate tones ................................................................................................................... 8

5.3 Abrasion resistance ............................................................................................................................................................................. 8

5.4 Resistance to toning ........................................................................................................................................................................... 9

5.5 Chemical resistance ........................................................................................................................................................................11

5.5.1 General...................................................................................................................................................................................11

5.5.2 Rub test .................................................................................................................................................................................11

5.5.3 Drop test ...............................................................................................................................................................................11

5.6 Plate performance for stop and restart ..........................................................................................................................11

6 The use of quality bands ............................................................................................................................................................................12

Annex A (informative) Examples of measurement method and results .......................................................................13

Annex B Example of evaluation results and classification .......................................................................................................22

Annex C (informative) Examples of quality grade reporting ....................................................................................................23

Bibliography .............................................................................................................................................................................................................................25

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ISO/DIS 24487-1:2021(E)
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

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established 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 standardization.

The procedures used to develop this document and those intended for its further maintenance are

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).

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 patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/ patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/

iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 130, Graphic technology.

A list of all parts in the ISO 24487 series can be found on the ISO website.

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.
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ISO/DIS 24487-1:2021(E)
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 viscosity 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 is Part 1 of a two-part series and specifies the following:

— Method of measurement of time to reach OK sheet including on-press development.

— Method of measurement of resistance to abrasion by quantitative means.
— Method of measurement of toning.
— Method of measurement of resistance to chemicals.

[Editor's note the bullet list above is not complete and will be completed when we finish the

development of this document.]

Part 2 specifies methods for extended evaluation of stability of performance including resistance to

deterioration for continuous use in various environment.
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DRAFT INTERNATIONAL STANDARD ISO/DIS 24487-1:2021(E)
Graphic technology — Processless plates —
Part 1:
Evaluation methods for characteristics and performance
1 Scope

This document applies to processless plates and specifies evaluation methods for plate characteristics,

on-press development performance, usability and print image quality.

It specifies measurement conditions for materials and equipment and provides guidelines for the

selection of suitable processless plates by a printing organization and requirements for comparative

assessment tests.
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 12647-2:2013, Graphic technology — Process control for the production of half-tone colour separations,

proof and production prints — Part 2: Offset lithographic processes

ISO 13655:2017, Graphic technology — Spectral measurement and colorimetric computation for graphic

arts images
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
processless plate

plate loaded directly on to a printing press following exposure without any intermediate processing

step other than mechanical processes such as plate punching and bending

Note 1 to entry: Intermediate processing steps typically include plate development, cleaning, fixing (or

desensitization) and other treatments

Note 2 to entry: Strictly speaking, these plates are 'processed' on press using the press fountain solution and ink.

3.2
on-press developability
assessment of performance of the plate development on printing press
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ISO/DIS 24487-1:2021(E)
3.3
ink receptivity on-press development

ink receptivity by the printing plate where the ink density gradually increases or decreases at the start

of printing

Note 1 to entry: Note to entry Commonly ink receptivity includes a stage where ink density stabilizes without

hunting and a stage where poor inking occurs during printing and where ink density decreases.

4 Test procedure
4.1 General

Printing machines in use today differ in physical structure, fountain technology and ink delivery

systems. The test conditions in this document are designed to be practical and to show significant

differentiation between performance of different processless plate technologies.

Test conditions have been chosen to control key factors that have an impact on processless plates

performance.
Two categories of testing are anticipated by this document:

Individual test: testing by a printer who wishes to choose the most suitable plate for his purpose and

for this category of test, the production methods and materials used for testing should be those used by

the printer for print production,

Comparative test: scientific testing to allow the performance of printing plates to be compared to

one another and for this category, the testing requires the use of specified test materials and methods

which in some cases may be specified by the press or plates manufacturer.

Unless explicitly indicated, requirements shall be applied to both testing categories.

4.2 Test environment
The temperature of the printing room shall be 24 ± 2 °C.
The relative humidity of the printing room shall be 55 ± 10 % RH.
4.3 Plate imaging

Printing plates shall be prepared to include the following content. Additional inked content shall be

added in such a way as to ensure approximately equal inking across the plate of between 20 %–40 %

coverage.

A CMYK test form with a set of rectangular or square patches shall be prepared comprising: a solid

(100 %) patch in each process colour, and patches of intermediate tones from 10 % to 70 % tone value

in each process colour. A region of at least 100 mm x 150 mm of the sheet shall be left blank (the non-

image area).

Each patch should have a minimum size of 10 mm x 10 mm and patches should be spaced by a minimum

of 5 mm. The plate image area shall have a large region of approximately half the total image size where

no marks are imaged. An example test form is shown in Figure 1.

NOTE the minimum size for each patch has been specified so that the patches may be measured easily. The

minimum spacing of patches is required to allow visual assessment of toning between printed elements.

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ISO/DIS 24487-1:2021(E)
Figure 1 — Example CMYK test form

The test form should be imaged in several positions and with different orientations. When oriented in

the press direction, it shall be aligned with the preferred printing direction as indicated.

NOTE Where a subset of the process inks is to be tested not all plates need to be imaged. For example, to test

the performance with cyan ink, only the cyan plate need be imaged.

The plates shall be exposed as recommended by the manufacturer for optimum image sensitivity and

should be adjusted to ensure that the halftone dot area on plate corresponds to patch tone value.

When printing is not 4-colour (CMYK), for example monochrome printing or printing of spot inks or

varnish, a test chart comprising the set of process colours generally used in print production shall be used.

Where abrasion resistance tests are to be performed, a monochrome test form comprising seven

sets of the patches shall be imaged. This test is generally performed on the black plate, but the same

monochrome image may also be used to image the cyan, magenta or yellow plate. An example of a

suitable test form is shown in Figure 2. Sets of patches shall be separated sufficiently to allow abrasion

resistance testing to be performed on one set without affecting any other set.
This test form may also be used when testing chemical resistance.
Figure 2 — Example abrasion resistance test form

When printing CMYK, all test forms shall be prepared and printed to meet the requirements of

ISO 12647-2 with the exception of the tone value increase which should not be adjusted from the

natural behaviour of the printing press. Additional content necessary for process control should be

added as required. The reference paper type that is closest to the paper actually used for printing shall

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ISO/DIS 24487-1:2021(E)

be identified and reported. When comparative testing is performed, a half-tone screen ruling of 60 cm

should be used.
NOTE This screen ruling is approximately equivalent to 150 lines per inch.
4.4 Pre-dampening amount

The pre-dampening amount should be as small as possible and shall be no greater than the recommended

value from the press vendor.
4.5 Pre-inking amount

The pre-inking amount shall be set to the recommended value from the plate manufacturer or press

vendor.
4.6 Ink selection

When individual testing is performed to determine whether the plate is suitable for a printing operation,

the inks used for testing should be the same as are typically used for production.

When comparative testing is performed, inks conforming to ISO 2846-1 shall be used.

For the evaluation of resistance to toning, a low viscosity and low tack ink with a large content of

varnish should be used.
Details of the inks used shall be reported.

NOTE Low viscosity and low tack inks show more differences when comparing processless plates.

4.7 Substrate selection

When individual testing is performed to determine whether the plate is suitable for a printing operation,

the substrates used for testing should be the same are typically used for production.

When comparative testing is performed, paper for the appropriate ISO 12647-2 printing condition shall

be used. Where possible, an environmentally friendly paper such as recycled paper and FSC certified

paper should be used.
Details of the substrate used shall be reported.
4.8 Fountain solution

When individual testing is performed to determine whether the plate is suitable for a printing operation,

the inks used for testing should be the same as are typically used for production.

When comparative testing is performed, a fountain solution recommended by the press manufacturer

shall be used. Where possible an environmentally friendly fountain solution should be used. Examples

of these fountain solutions are listed on the website of Fogra e.V. (www .fogra .org).

Dilution of the fountain solution shall be made as recommended by the printing press manufacturer.

The fountain solution and dilution amount used shall be reported.
4.9 Press preparation and control

The number of sheets required for plate development depends on the press condition when the print run

starts and can vary by more than a factor of two. To avoid this problem a set of identical plates should

be used for a previous press run of at least 300 sheets during which ink key settings are established.

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ISO/DIS 24487-1:2021(E)

During this press run, the press settings should be established according to the press and plate

manufacturer's recommendation. The blanket should then be washed before the plates to be tested are

fitted to the press and the testing begins.

Note The start-up procedure according to plate manufacturer’s and press manufacturer’s recommendation

can be different for each press or plate.

The press shall be adjusted to achieve the printing aims within the deviation tolerances as specified in

ISO 12647-2 for the solid cyan, magenta, yellow and black process colorants and all patches are within

the variation tolerances.

Printing speed should be the speed generally used for print production or a standard setting as

recommended by the press manufacturer. Press speed shall be reported.

Other press parameters such as fountain solution cooling temperature, ink roller cooling temperature,

blanket, water supply system, water supply slip ratio and impression throw-in should be operated as

recommended by the press manufacturer. In cases where the press is operated differently from that

recommended by the manufacturer, the differences shall be reported.

Where available, press manufacturer recommended programs for processless plates should be

used. Where no such recommendation exists, the same press condition as is used for printing using

conventional plates shall be used.

When comparative testing is performed, details of the press type and press configuration shall be

reported.
4.9.1 Reference printing aim values

A set of sheets shall be selected from the end of this press preparation print run that are within the

specified tolerance and shall be measured to establish reference aim values for all coloured patches and

for the unprinted substrate.
4.10 Printing method

Using the printing procedure recommended by the printing press manufacturer or, when individual

tests are performed, by the standard printing method used by the printing operation, approximately

100 sheets should be printed after on-press development is observed by the press operator to be

complete.

NOTE Printing procedures include adjustment of ink roller and dampening roller settings, adjustment of

spacing between plate and blanket cylinder, balance between water and ink, and blanket freshening.

Where assessment of toning, chemical resistance and press stop-and-restart is performed, additional

prints shall be made as follows. Print an additional 1000 sheets using the standard printing procedure

before stopping the press. The last 30 sheets before stopping shall be collected. The press shall be

stopped for one hour. The press shall be restarted and at least 100 additional sheets printed.

The press state during the period where the press is stopped can affect the stop-and-restart testing.

The best result can be different for each press or plate type and so where they exist, the manufacturers'

recommendations for press stop-and-restart should be used.

The last 30 sheets collected before the press is stopped are used to evaluate toning performance.

The last 30 sheets collected before the press is stopped along with sheets 70-100 printed following the

restart are used to evaluate chemical resistance and stop-and-restart performance.

4.11 Plate exposure to light

The performance of some plates is affected when exposed to light. This can happen when plates are

prepared and placed next to the press during a previous print run as is often done.

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ISO/DIS 24487-1:2021(E)

In order to test the effect of light exposure on the plates, a set of plates shall be produced and exposed

to typical pressroom lighting for a period of one hour.

Where comparative testing is performed, the lighting condition of ISO 4892-2, filtered xenon-arc light

source (daylight behind window glass), should be used.

Plates for this test should be new and stored in a dark place before the test begins.

5 Assessment methods
5.1 General
The following test methods are designed to evaluate processless plates.

NOTE Some of these test methods can also be used to evaluate standard process plate properties.

5.2 On-press development
5.2.1 Number of sheets required for on-press development

Figure 3 shows the typical relationship between the number of sheets printed and the CIELAB colour

change for each region of the plate.

NOTE The curve shapes shown in Figure 3 may vary significantly from one press to another, may depend on

the processless plates, and may depend on the start-up condition of the press.
Key
a Colour change of solid image area
b Colour change of intermediate tones image of non-image
c Colour change or non-image area
Figure 3 — Typical colour coordinates and tone values by number of sheets

The press shall be started, and the colour of regions a, b and c shall be monitored until:

— the colour of regions a and b match the printing aim values established in 4.9.1 to within the variation

tolerances of ISO 12647-2,
— no ink is visible on the non-image area (region c) and

— the colour of the unprinted sheet matches the reference (see 4.9.1) to within the variation tolerance

specified in ISO 12647-2.
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ISO/DIS 24487-1:2021(E)

The set of sheets printed from the time the press is started shall be numbered and the sheet number

where all conditions are met shall be identified. The number of this sheet is defined as the number of

sheets required for on-press development.
Details of how to print and measure the sheets are provided in Annex A.
5.2.2 Assessment of non-image area

Assessment of the non-image area provides an indication of the effective removal of the photosensitive

layer. The maximum density of the non-image area generated during the on-press development period

affects the toning in the printing press and the quality of the prints and provides a measure of the

effectiveness of on-press development.

Sheets shall be assessed by visual inspection using a loupe to ensure that no ink is visible on the

unprinted region. Care shall be taken to check that the edges of the printed region are sharply defined

with no residual ink beyond the edge.

The number of sheets required to reach the point where the printed matter does not have any visible

ink shall be recorded along with the maximum density on any of the sheets printed from the time the

press is started.
When the ink spreads over the enti
...