ISO 24487-1:2021
(Amendment)Graphic technology — Processless lithographic plates — Part 1: Evaluation methods for characteristics and performance
Graphic technology — Processless lithographic plates — Part 1: Evaluation methods for characteristics and performance
This document applies to processless lithographic plates and specifies evaluation methods for lithographic 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 lithographic plates by a printing organization and requirements for comparative assessment tests. The assessment of waterless lithographic plates is out of scope of this document.
Technologie graphique — Plaques lithographiques sans traitement — Partie 1: Méthodes d'évaluation des caractéristiques et des performances
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INTERNATIONAL ISO
STANDARD 24487-1
First edition
2021-11
Graphic technology — Processless
lithographic plates —
Part 1:
Evaluation methods for characteristics
and performance
Technologie graphique — Plaques lithographiques sans traitement —
Partie 1: Méthodes d'évaluation des caractéristiques et des
performances
Reference number
ISO 24487-1:2021(E)
© ISO 2021
---------------------- Page: 1 ----------------------
ISO 24487-1:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
© ISO 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 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 ................................................................................................................................................................................. 5
4.9 Press preparation and control .................................................................................................................................................. 5
4.9.1 Press preparation print run ..................................................................................................................................... 5
4.9.2 Reference printing aim values ............................................................................................................................... 5
4.10 Printing method .................................................................................................................................................................................... 6
4.11 Plate exposure to light ..................................................................................................................................................................... 6
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 ......... .................................................................................................................................. ................................. 9
5.4 Resistance to toning .......................................................................................................................................................................... 9
5.5 Chemical resistance ....................................................................................................................................................................... 11
5.5.1 General ..................................................................................................................................................................................... 11
5.5.2 Rub test ....................................................................................................................................................................................12
5.5.3 Drop test .................................................................................................................................................................................12
5.6 Plate performance for stop and restart .........................................................................................................................12
6 Reporting requirements ...........................................................................................................................................................................12
Annex A (informative) Examples of measurement method and results .....................................................................14
Annex B (informative) Example of evaluation results and classification .................................................................26
Annex C (informative) Examples of quality grade reporting .................................................................................................27
Bibliography .............................................................................................................................................................................................................................29
iii© ISO 2021 – All rights reserved
---------------------- Page: 3 ----------------------
ISO 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.© ISO 2021 – All rights reserved
---------------------- Page: 4 ----------------------
ISO 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.
© ISO 2021 – All rights reserved---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO 24487-1:2021(E)
Graphic technology — Processless lithographic plates —
Part 1:
Evaluation methods for characteristics and performance
1 Scope
This document applies to processless lithographic plates and specifies evaluation methods for
lithographic 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 lithographic plates by a printing organization and requirements for
comparative assessment tests.The assessment of waterless lithographic plates is out of scope of this document.
2 Normative referencesThe 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 2846-1, Graphic technology — Colour and transparency of printing ink sets for four-colour printing —
Part 1: Sheet-fed and heat-set web offset lithographic printingISO 12647-2, Graphic technology — Process control for the production of half-tone colour separations,
proof and production prints — Part 2: Offset lithographic processesISO 13655, Graphic technology — Spectral measurement and colorimetric computation for graphic arts
images3 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 https:// 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 bendingNote 1 to entry: Intermediate processing steps typically include plate development, cleaning, fixing (or
desensitization) and other treatmentsNote 2 to entry: Strictly speaking, these plates are 'processed' on press using the press fountain solution and ink.
3.2pre-dampening amount
fountain solution amount used to wet plates prior to printing
© ISO 2021 – All rights reserved
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ISO 24487-1:2021(E)
3.3
pre-inking amount
ink amount applied to plates prior to printing
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.
a) 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.b) 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 environmentThe temperature of the printing room shall be 24 °C ± 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 % to 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 × 150 mm of the sheet shall be left blank (the non-
image area).Each patch should have a minimum size of 10 mm × 10 mm and patches should be spaced by a minimum
of 5 mm. Where visual assessment is required, patches should have a minimum size of 40 mm × 40 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 1 The minimum size for each patch has been specified so that the patches can be measured easily. The
minimum spacing of patches is required to allow visual assessment of toning between printed elements.
© ISO 2021 – All rights reserved---------------------- Page: 7 ----------------------
ISO 24487-1:2021(E)
Key
A preferred printing direction
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 2 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 needs to 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.
© ISO 2021 – All rights reserved
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ISO 24487-1:2021(E)
Key
A preferred printing direction
B abrasion direction
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
be identified and reported. When comparative testing is performed, a half-tone screen ruling of 60 cm
(approximately 150 lines per inch) should be used.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 selectionWhen individual testing is performed to determine whether the plate is suitable for a printing operation,
the substrates used for testing should be the same as 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.© ISO 2021 – All rights reserved
---------------------- Page: 9 ----------------------
ISO 24487-1:2021(E)
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 fountain solution 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. A list of
fountain concentrates tested by Fogra and approved by the printing press manufacturers is given in
Reference [2].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
4.9.1 Press preparation print run
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, two sets of identical plates
shall be prepared. The first set shall be used for a press preparation print run of at least 300 sheets
during which ink key settings are established and the second set shall be used for the test print run.
During the press preparation press run, the press settings should be established according to the press
and plate manufacturer's recommendation. The blanket shall then be washed and dried before the
plates to be tested are fitted to the press and the testing begins.NOTE The start-up procedure according to the plate manufacturer’s and the 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 shall 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, slip ratio between fountain solution rollers 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.All settings and materials necessary to repeat the result of the press preparation print run shall be
reported.4.9.2 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.© ISO 2021 – All rights reserved
---------------------- Page: 10 ----------------------
ISO 24487-1:2021(E)
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 1 000 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 to 100 printed following
the restart, are used to evaluate chemical resistance and stop-and-restart performance.
4.11 Plate exposure to lightThe 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.
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 1 h.Where comparative testing is performed, the lighting condition of ISO 3664 P2 should be used.
Plates for this test should be new and stored in a dark place before the test begins.
5 Assessment methods5.1 General
The following test methods are designed to evaluate processless plates. Measurements shall be made in
accordance with ISO 13655. ISO 3664 viewing condition P2 should be used for visual assessment.
NOTE Some of these test methods can also be used to evaluate standard process plate properties.
Examples of reporting of results are shown in Annex B.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 can vary significantly from one press to another, can depend on
the processless plates, and can depend on the start-up condition of the press.© ISO 2021 – All rights reserved
---------------------- Page: 11 ----------------------
ISO 24487-1:2021(E)
Key
X number of sheets
Y ΔE from substrate
1 colour change of solid image area
2 colour change of intermediate tones
3 colour change of 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 1, 2 and 3 shall be monitored until:
— the colour of regions 1 and 2 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 3), and
— the colour of the unprinted sheet matches the reference (see 4.9.1) to within the variation tolerance
specified in ISO 12647-2.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 CIELAB76 colour difference between the print area and
the unprinted substrate colour on any of the sheets printed from the time the press is started.
When the ink spreads over the entire surface of the plate, excess ink contaminates the printing press
and can cause various quality failures. The maximum ink density in the non-image area provides a
measure of the effectiveness of on-press development.© ISO 2021 – All rights reserved
---------------------- Page: 12 ----------------------
ISO 24487-1:2021(E)
Key
1 exposed plate
2 plate covered with fountain solution
3 plate covered with ink
4 plate with ink remaining only on halftone dots
Figure 4 — Fountain solution and ink spread
Figure 4 shows the steps in the formation of the non-image area. The exposed plate is co
...FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 24487-1
ISO/TC 130
Graphic technology — Processless
Secretariat: SAC
plates —
Voting begins on:
2021-08-06
Part 1:
Voting terminates on:
Evaluation methods for characteristics
2021-10-01
and performance
RECIPIENTS OF THIS DRAFT ARE INVITED TO
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/FDIS 24487-1:2021(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN-
DARDS TO WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS. ISO 2021
---------------------- Page: 1 ----------------------
ISO/FDIS 24487-1:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/FDIS 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 .................................................................................................................................................................................. 5
4.9 Press preparation and control ................................................................................................................................................... 5
4.9.1 Press preparation print run ................................................................................................................................... 5
4.9.2 Reference printing aim values .............................................................................................................................. 5
4.10 Printing method ..................................................................................................................................................................................... 6
4.11 Plate exposure to light ...................................................................................................................................................................... 6
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 ............................................................................................................................................................................. 9
5.4 Resistance to toning ........................................................................................................................................................................... 9
5.5 Chemical resistance ........................................................................................................................................................................11
5.5.1 General...................................................................................................................................................................................11
5.5.2 Rub test .................................................................................................................................................................................12
5.5.3 Drop test ...............................................................................................................................................................................12
5.6 Plate performance for stop and restart ..........................................................................................................................12
6 Reporting requirements ............................................................................................................................................................................12
Annex A (informative) Examples of measurement method and results .......................................................................14
Annex B (informative) Example of evaluation results and classification ....................................................................26
Annex C (informative) Examples of quality grade reporting ....................................................................................................27
Bibliography .............................................................................................................................................................................................................................29
© ISO 2021 – All rights reserved iii---------------------- Page: 3 ----------------------
ISO/FDIS 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.iv © ISO 2021 – All rights reserved
---------------------- Page: 4 ----------------------
ISO/FDIS 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.
© ISO 2021 – All rights reserved v---------------------- Page: 5 ----------------------
FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 24487-1:2021(E)
Graphic technology — Processless plates —
Part 1:
Evaluation methods for characteristics and performance
1 Scope
This document applies to processless lithographic plates and specifies evaluation methods for
lithographic 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 lithographic plates by a printing organization and requirements for
comparative assessment tests.The assessment of waterless lithographic plates is out of scope of this document.
2 Normative referencesThe 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 2846-1, Graphic technology — Colour and transparency of printing ink sets for four-colour printing —
Part 1: Sheet-fed and heat-set web offset lithographic printingISO 12647-2, Graphic technology — Process control for the production of half-tone colour separations,
proof and production prints — Part 2: Offset lithographic processesISO 13655, Graphic technology — Spectral measurement and colorimetric computation for graphic arts
images3 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 https:// 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 bendingNote 1 to entry: Intermediate processing steps typically include plate development, cleaning, fixing (or
desensitization) and other treatmentsNote 2 to entry: Strictly speaking, these plates are 'processed' on press using the press fountain solution and ink.
3.2pre-dampening amount
fountain solution amount used to wet plates prior to printing
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ISO/FDIS 24487-1:2021(E)
3.3
pre-inking amount
ink amount applied to plates prior to printing
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.
a) 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.b) 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 environmentThe temperature of the printing room shall be 24 °C ± 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 % to 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 × 150 mm of the sheet shall be left blank (the non-
image area).Each patch should have a minimum size of 10 mm × 10 mm and patches should be spaced by a minimum
of 5 mm. Where visual assessment is required, patches should have a minimum size of 40 mm x 40 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 1 The minimum size for each patch has been specified so that the patches can be measured easily. The
minimum spacing of patches is required to allow visual assessment of toning between printed elements.
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Key
A preferred printing direction
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 2 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 needs to 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.
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Key
A preferred printing direction
B abrasion direction
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
be identified and reported. When comparative testing is performed, a half-tone screen ruling of 60 cm
(approximately 150 lines per inch) should be used.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 selectionWhen individual testing is performed to determine whether the plate is suitable for a printing operation,
the substrates used for testing should be the same as 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.4 © ISO 2021 – All rights reserved
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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 fountain solution 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. A list of
fountain concentrates tested by Fogra and approved by the printing press manufacturers is given in
Reference [2].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
4.9.1 Press preparation print run
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, two sets of identical plates
shall be prepared. The first set shall be used for a press preparation print run of at least 300 sheets
during which ink key settings are established and the second set shall be used for the test print run.
During the press preparation press run, the press settings should be established according to the press
and plate manufacturer's recommendation. The blanket shall then be washed and dried before the
plates to be tested are fitted to the press and the testing begins.NOTE The start-up procedure according to the plate manufacturer’s and the 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 shall 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, slip ratio between fountain solution rollers 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.All settings and materials necessary to repeat the result of the press preparation print run shall be
reported.4.9.2 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
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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 1 000 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 to 100 printed following
the restart, are used to evaluate chemical resistance and stop-and-restart performance.
4.11 Plate exposure to lightThe 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.
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 1 h.Where comparative testing is performed, the lighting condition of ISO 3664 P2 should be used.
Plates for this test should be new and stored in a dark place before the test begins.
5 Assessment methods5.1 General
The following test methods are designed to evaluate processless plates. Measurements shall be made in
accordance with ISO 13655. ISO 3664 viewing condition P2 should be used for visual assessment.
NOTE Some of these test methods can also be used to evaluate standard process plate properties.
Examples of reporting of results are shown in Annex B.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 can vary significantly from one press to another, can depend on
the processless plates, and can depend on the start-up condition of the press.6 © ISO 2021 – All rights reserved
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Key
X number of sheets
Y ΔE from substrate
1 colour change of solid image area
2 colour change of intermediate tones image of non-image
3 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.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 CIELAB76 colour difference between the print area and
the unprinted substrate colour on any of the sheets printed from the time the press is started.
When the ink spreads over the entire surface of the plate, excess ink contaminates the printing press
and can cau...
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