Graphic technology — Laboratory preparation of test prints — Part 2: Liquid printing inks

This document specifies a test method for preparation of test prints produced with liquid printing inks, either water-based, solvent-based or radiation cured printing inks as used in flexography and gravure printing. Such test prints are intended to be used for reflection-based measurements, such as colorimetry and optical density as well as for testing light fastness, and the resistance of printing inks to mechanical and chemical attack regarding either printing ink and/or substrate. This document is not applicable to inks for ink jet printing.

Technologie graphique — Préparation en laboratoire des impressions d'essai — Partie 2: Encres d'impression liquides

Grafična tehnologija - Laboratorijska izdelava preskusnih odtisov - 2. del: Tekoče tiskarske barve

Ta dokument določa preskusno metodo za pripravo preskusnih odtisov, izdelanih s tekočimi tiskarskimi barvami, ki so bodisi na vodni osnovi, na osnovi topil ali na osnovi tiskarskih barv, ki se strjujejo s sevanjem, ki se uporabljajo pri fleksotisku in globokem tisku. Takšni preskusni izpisi so namenjeni uporabi za meritve na podlagi odseva, kot sta kolorimetrija in optična gostota, ter za preskušanje obstojnosti na svetlobi in odpornosti tiskarskih barv na mehanske in kemične vplive tiskarske barve in/ali podlage. Ta dokument se ne uporablja za tiskarske barve za brizgalno tiskanje.

General Information

Status
Published
Publication Date
30-Nov-2022
Current Stage
6060 - International Standard published
Start Date
01-Dec-2022
Due Date
08-Dec-2022
Completion Date
01-Dec-2022

Relations

Buy Standard

Standard
ISO 2834-2:2023
English language
15 pages
sale 10% off
Preview
sale 10% off
Preview
e-Library read for
1 day
Standard
ISO 2834-2:2022 - Graphic technology — Laboratory preparation of test prints — Part 2: Liquid printing inks Released:1. 12. 2022
English language
10 pages
sale 15% off
Preview
sale 15% off
Preview

Standards Content (Sample)

SLOVENSKI STANDARD
SIST ISO 2834-2:2023
01-april-2023
Nadomešča:
SIST ISO 2834-2:2016
Grafična tehnologija - Laboratorijska izdelava preskusnih odtisov - 2. del: Tekoče
tiskarske barve
Graphic technology - Laboratory preparation of test prints - Part 2: Liquid printing inks
Technologie graphique — Préparation en laboratoire des impressions d'essai — Partie
2: Encres d'impression liquides
Ta slovenski standard je istoveten z: ISO 2834-2:2022
ICS:
87.080 Barvila. Tiskarske barve Inks. Printing inks
SIST ISO 2834-2:2023 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST ISO 2834-2:2023

---------------------- Page: 2 ----------------------
SIST ISO 2834-2:2023
INTERNATIONAL ISO
STANDARD 2834-2
Third edition
2022-12
Graphic technology — Laboratory
preparation of test prints —
Part 2:
Liquid printing inks
Technologie graphique — Préparation en laboratoire des impressions
d'essai —
Partie 2: Encres d'impression liquides
Reference number
ISO 2834-2:2022(E)
© ISO 2022

---------------------- Page: 3 ----------------------
SIST ISO 2834-2:2023
ISO 2834-2:2022(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2022
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 2022 – All rights reserved

---------------------- Page: 4 ----------------------
SIST ISO 2834-2:2023
ISO 2834-2:2022(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Test method . 2
4.1 Principle . 2
4.2 Apparatus and quality requirements . 2
4.2.1 Apparatus . 2
4.2.2 Quality requirements for laboratory proofers . 5
4.3 Materials . 5
4.3.1 Printing ink . 5
4.3.2 Printing substrate . 6
4.4 Test conditions . 6
4.4.1 Climatic conditions . 6
4.4.2 Printing speed and printing pressure . 6
4.4.3 Drying . 6
4.4.4 Determination of ink film coverage and ink film thickness . 6
5 Procedure .8
6 Test report . 8
Bibliography .10
iii
© ISO 2022 – All rights reserved

---------------------- Page: 5 ----------------------
SIST ISO 2834-2:2023
ISO 2834-2:2022(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.
This third edition cancels and replaces the second edition (ISO 2834-2:2015), which has been technically
revised.
The main changes are as follows:
— parameters describing the preparation of printing forms and anilox cylinders are replaced by data
(to be acquired by the user of this document) describing the ink transfer of particular settings of
tester, printing forme, ink and substrate.
A list of all parts in the ISO 2834 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 2022 – All rights reserved

---------------------- Page: 6 ----------------------
SIST ISO 2834-2:2023
ISO 2834-2:2022(E)
Introduction
This document describes the test print preparation of liquid inks (gravure and flexography). These
test prints have a homogeneous distribution of ink on a substrate, a reproducible ink composition and
relative ink coverage. Therefore, they are suitable for optical tests so that the measured reflectance
can be assigned to a known ink coverage. If tests are done only for mechanical and chemical resistance,
the user may apply less accurate methods. The preparation of test prints for paste inks (lithography) is
described in ISO 2834-1, while screen inks are covered in ISO 2834-3.
In ISO 2834-1, specific operational settings for the “round-to-round” and the “round-to-flat” offset ink
printability testers are provided. Laboratory proofers (printability testers) for liquid inks encompass
a much wider array of operating processes and associated settings. Therefore, the guidelines included
in ISO 2834-2 are more general and will, of necessity, result in more opportunities for operator error in
making the test prints.
v
© ISO 2022 – All rights reserved

---------------------- Page: 7 ----------------------
SIST ISO 2834-2:2023

---------------------- Page: 8 ----------------------
SIST ISO 2834-2:2023
INTERNATIONAL STANDARD ISO 2834-2:2022(E)
Graphic technology — Laboratory preparation of test
prints —
Part 2:
Liquid printing inks
1 Scope
This document specifies a test method for preparation of test prints produced with liquid printing
inks, either water-based, solvent-based or radiation cured printing inks as used in flexography and
gravure printing. Such test prints are intended to be used for reflection-based measurements, such as
colorimetry and optical density as well as for testing light fastness, and the resistance of printing inks
to mechanical and chemical attack regarding either printing ink and/or substrate. This document is not
applicable to inks for ink jet printing.
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 187, Paper, board and pulps — Standard atmosphere for conditioning and testing and procedure for
monitoring the atmosphere and conditioning of samples
ISO 13655, 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 terminology 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
anilox roller
chromium plated or ceramic roller with evenly distributed small cells generally mounted on a
flexographic printing press to control the quantity of ink transferred to the printing forme
3.2
extender
transparent material (varnish or polymer solution) used to reduce the colorant concentration while
maintaining viscosity to adapt ink colour concentration to print substrates
1
© ISO 2022 – All rights reserved

---------------------- Page: 9 ----------------------
SIST ISO 2834-2:2023
ISO 2834-2:2022(E)
3.3
laboratory proofer
printability tester
device for uniformly applying a reproducible amount of ink to a substrate under specified conditions
Note 1 to entry: Earlier editions of this document used the term "printability tester" which is still commonly used
in the market.
3.4
flexographic printing forme
cylinder or sleeve covered with a relief type rubber or photopolymer plate for application of printing ink
(3.6) to print substrate
3.5
gravure printing forme
mechanically engraved, laser-engraved or chemically etched cylinder, sleeve or plate for application of
printing ink (3.6) to a print substrate
3.6
printing ink
composite material containing colorants, functional components, vehicle and additives
Note 1 to entry: In most cases, it is applied as a fluid to a substrate by a printing process and it is setting or drying
by either physical (evaporation) and/or chemical (polymerizations, e.g. oxidation, radiation induced, or other)
processes in order to form an image for decorative, informative or technical purposes.
3.7
retarder
additive to reduce the evaporation speed of the solvent in a liquid ink to prevent drying during the
application of ink to the substrate
3.8
test-ready ink
printing ink (3.6) of the appropriate composition and viscosity for the purpose of the test
4 Test method
4.1 Principle
Using a laboratory proofer, the gravure or flexographic printing ink is applied consistently and uniformly
on the chosen substrate. The ink transfer depends on many aspects of the proofer, the printing forme,
the ink and the substrate. For each individual setting, the ink transfer shall be determined according to
any method described in 4.4.4. As long as there are no changes in these settings and the printing forms
are cleaned thoroughly, the ink transfer is constant.
NOTE 1 Test samples for mechanical and chemical resistance tests can be prepared using any technique
resulting in a uniform ink film in a desired thickness range. Ink film thicknesses different from those used in
practice will have a strong influence on the results of such tests. These methods are not covered by this document.
NOTE 2 Due to differences between a printing press and a laboratory proofer, prints produced on a laboratory
proofer can be different in appearance and in ink film thickness from commercial prints. To reach the same
colour strength or print density, different settings from the actual press settings are generally required.
4.2 Apparatus and quality requirements
4.2.1 Apparatus
Any laboratory proofer for liquid printing inks of the type to be tested, liquid printing ink (solvent,
water or radiation cured), substrate and drying apparatus may be used as long as the resulting printed
2
  © ISO 2022 – All rights reserved

---------------------- Page: 10 ----------------------
SIST ISO 2834-2:2023
ISO 2834-2:2022(E)
ink film is uniform and at the required ink film thickness. Test conditions and variables associated
with such equipment and materials shall be agreed upon between parties since variations in design
and process have a strong influence on the test results and comparability of the properties of the test
sample.
4.2.1.1 Laboratory proofer
To ensure repeatable operation, the laboratory proofer shall provide automated control of the ink
transfer function. It is not practical to duplicate exactly a commercial production printing process in the
laboratory. However, it is possible to duplicate results between two laboratories. The chosen laboratory
proofer shall provide a consistent, uniform printed ink film at the required ink film thickness. To
achieve this control, the printing speed and the pressure or impression (for flexography) between the
printing forme and printing substrate shall be adjustable and shall be constant and uniform during the
printing process.
For gravure, the Shore hardness of the pressure roller as well as the use of an electrostatic printing aid
shall be agreed upon and specified. For flexography, the anilox roller (see also 4.2.1.3) and the type of
blade or doctoring device shall be specified.
NOTE The Shore hardness, compressibility and smoothness of the impression roller depend on the
purpose of the test. There are different pressure roller surfaces in the market. Often, these are harder plastic
surfaces typically measured as Shore D and sometimes softer surfaces are used to be measured as Shore A.
Guidance on the use of shore measurement can be found in corresponding ISO Standards.
The determination of the Shore hardness requires a minimum thickness of the material to be tested. This
sometimes is not present.
4.2.1.2 Printing formes
4.2.1.2.1 Gravure printing forme
These may be produced by electromechanical engraving, laser engraving or chemical etching. Printing
formes can contain solid and tinted areas. The design of printing formes can either be of a standard
layout with a designation of the supplier of the laboratory proofer or special with respect to customer
needs.
...

INTERNATIONAL ISO
STANDARD 2834-2
Third edition
2022-12
Graphic technology — Laboratory
preparation of test prints —
Part 2:
Liquid printing inks
Technologie graphique — Préparation en laboratoire des impressions
d'essai —
Partie 2: Encres d'impression liquides
Reference number
ISO 2834-2:2022(E)
© ISO 2022

---------------------- Page: 1 ----------------------
ISO 2834-2:2022(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2022
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 2022 – All rights reserved

---------------------- Page: 2 ----------------------
ISO 2834-2:2022(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Test method . 2
4.1 Principle . 2
4.2 Apparatus and quality requirements . 2
4.2.1 Apparatus . 2
4.2.2 Quality requirements for laboratory proofers . 5
4.3 Materials . 5
4.3.1 Printing ink . 5
4.3.2 Printing substrate . 6
4.4 Test conditions . 6
4.4.1 Climatic conditions . 6
4.4.2 Printing speed and printing pressure . 6
4.4.3 Drying . 6
4.4.4 Determination of ink film coverage and ink film thickness . 6
5 Procedure .8
6 Test report . 8
Bibliography .10
iii
© ISO 2022 – All rights reserved

---------------------- Page: 3 ----------------------
ISO 2834-2:2022(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.
This third edition cancels and replaces the second edition (ISO 2834-2:2015), which has been technically
revised.
The main changes are as follows:
— parameters describing the preparation of printing forms and anilox cylinders are replaced by data
(to be acquired by the user of this document) describing the ink transfer of particular settings of
tester, printing forme, ink and substrate.
A list of all parts in the ISO 2834 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 2022 – All rights reserved

---------------------- Page: 4 ----------------------
ISO 2834-2:2022(E)
Introduction
This document describes the test print preparation of liquid inks (gravure and flexography). These
test prints have a homogeneous distribution of ink on a substrate, a reproducible ink composition and
relative ink coverage. Therefore, they are suitable for optical tests so that the measured reflectance
can be assigned to a known ink coverage. If tests are done only for mechanical and chemical resistance,
the user may apply less accurate methods. The preparation of test prints for paste inks (lithography) is
described in ISO 2834-1, while screen inks are covered in ISO 2834-3.
In ISO 2834-1, specific operational settings for the “round-to-round” and the “round-to-flat” offset ink
printability testers are provided. Laboratory proofers (printability testers) for liquid inks encompass
a much wider array of operating processes and associated settings. Therefore, the guidelines included
in ISO 2834-2 are more general and will, of necessity, result in more opportunities for operator error in
making the test prints.
v
© ISO 2022 – All rights reserved

---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO 2834-2:2022(E)
Graphic technology — Laboratory preparation of test
prints —
Part 2:
Liquid printing inks
1 Scope
This document specifies a test method for preparation of test prints produced with liquid printing
inks, either water-based, solvent-based or radiation cured printing inks as used in flexography and
gravure printing. Such test prints are intended to be used for reflection-based measurements, such as
colorimetry and optical density as well as for testing light fastness, and the resistance of printing inks
to mechanical and chemical attack regarding either printing ink and/or substrate. This document is not
applicable to inks for ink jet printing.
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 187, Paper, board and pulps — Standard atmosphere for conditioning and testing and procedure for
monitoring the atmosphere and conditioning of samples
ISO 13655, 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 terminology 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
anilox roller
chromium plated or ceramic roller with evenly distributed small cells generally mounted on a
flexographic printing press to control the quantity of ink transferred to the printing forme
3.2
extender
transparent material (varnish or polymer solution) used to reduce the colorant concentration while
maintaining viscosity to adapt ink colour concentration to print substrates
1
© ISO 2022 – All rights reserved

---------------------- Page: 6 ----------------------
ISO 2834-2:2022(E)
3.3
laboratory proofer
printability tester
device for uniformly applying a reproducible amount of ink to a substrate under specified conditions
Note 1 to entry: Earlier editions of this document used the term "printability tester" which is still commonly used
in the market.
3.4
flexographic printing forme
cylinder or sleeve covered with a relief type rubber or photopolymer plate for application of printing ink
(3.6) to print substrate
3.5
gravure printing forme
mechanically engraved, laser-engraved or chemically etched cylinder, sleeve or plate for application of
printing ink (3.6) to a print substrate
3.6
printing ink
composite material containing colorants, functional components, vehicle and additives
Note 1 to entry: In most cases, it is applied as a fluid to a substrate by a printing process and it is setting or drying
by either physical (evaporation) and/or chemical (polymerizations, e.g. oxidation, radiation induced, or other)
processes in order to form an image for decorative, informative or technical purposes.
3.7
retarder
additive to reduce the evaporation speed of the solvent in a liquid ink to prevent drying during the
application of ink to the substrate
3.8
test-ready ink
printing ink (3.6) of the appropriate composition and viscosity for the purpose of the test
4 Test method
4.1 Principle
Using a laboratory proofer, the gravure or flexographic printing ink is applied consistently and uniformly
on the chosen substrate. The ink transfer depends on many aspects of the proofer, the printing forme,
the ink and the substrate. For each individual setting, the ink transfer shall be determined according to
any method described in 4.4.4. As long as there are no changes in these settings and the printing forms
are cleaned thoroughly, the ink transfer is constant.
NOTE 1 Test samples for mechanical and chemical resistance tests can be prepared using any technique
resulting in a uniform ink film in a desired thickness range. Ink film thicknesses different from those used in
practice will have a strong influence on the results of such tests. These methods are not covered by this document.
NOTE 2 Due to differences between a printing press and a laboratory proofer, prints produced on a laboratory
proofer can be different in appearance and in ink film thickness from commercial prints. To reach the same
colour strength or print density, different settings from the actual press settings are generally required.
4.2 Apparatus and quality requirements
4.2.1 Apparatus
Any laboratory proofer for liquid printing inks of the type to be tested, liquid printing ink (solvent,
water or radiation cured), substrate and drying apparatus may be used as long as the resulting printed
2
  © ISO 2022 – All rights reserved

---------------------- Page: 7 ----------------------
ISO 2834-2:2022(E)
ink film is uniform and at the required ink film thickness. Test conditions and variables associated
with such equipment and materials shall be agreed upon between parties since variations in design
and process have a strong influence on the test results and comparability of the properties of the test
sample.
4.2.1.1 Laboratory proofer
To ensure repeatable operation, the laboratory proofer shall provide automated control of the ink
transfer function. It is not practical to duplicate exactly a commercial production printing process in the
laboratory. However, it is possible to duplicate results between two laboratories. The chosen laboratory
proofer shall provide a consistent, uniform printed ink film at the required ink film thickness. To
achieve this control, the printing speed and the pressure or impression (for flexography) between the
printing forme and printing substrate shall be adjustable and shall be constant and uniform during the
printing process.
For gravure, the Shore hardness of the pressure roller as well as the use of an electrostatic printing aid
shall be agreed upon and specified. For flexography, the anilox roller (see also 4.2.1.3) and the type of
blade or doctoring device shall be specified.
NOTE The Shore hardness, compressibility and smoothness of the impression roller depend on the
purpose of the test. There are different pressure roller surfaces in the market. Often, these are harder plastic
surfaces typically measured as Shore D and sometimes softer surfaces are used to be measured as Shore A.
Guidance on the use of shore measurement can be found in corresponding ISO Standards.
The determination of the Shore hardness requires a minimum thickness of the material to be tested. This
sometimes is not present.
4.2.1.2 Printing formes
4.2.1.2.1 Gravure printing forme
These may be produced by electromechanical engraving, laser engraving or chemical etching. Printing
formes can contain solid and tinted areas. The design of printing formes can either be of a standard
layout with a designation of the supplier of the laboratory proofer or special with respect to customer
needs. Printing forms containing half-tone images are not covered in this document. Printing formes
shall have a designation. Printing forms should contain 100 % tone value patches with an area of at
2
least 1 600 mm .
Gravure printing formes should be specified by the amount of ink transferred for each tone value
present and shall be specified by the amount of ink transferred for the 100 % tone value. The transfer
characteristic of the forme shall be characterized according to either method described in 4.
...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.