© ISO 2015 Graphic technology — Process control for the manufacture of half tone colour separations, proof and production prints — Part 5 Screen printing Technologie graphique — Contrôle du processus[.]
INTERNATIONAL STANDARD ISO 12647-5 Second edition 2015-01-15 Graphic technology — Process control for the manufacture of halftone colour separations, proof and production prints — Part 5: Screen printing Technologie graphique — Contrôle du processus de confection de sélections couleurs tramées, d’épreuves et de tirages — Partie 5: Sérigraphie Reference number ISO 12647-5:2015(E) © ISO 2015 ISO 12647-5:2015(E) COPYRIGHT PROTECTED DOCUMENT © ISO 2015 All rights reserved Unless otherwise specified, no part o f 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 o f the requester ISO copyright o ffice Case postale 56 • CH-1211 Geneva 20 Tel + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyright@iso.org Web www.iso.org Published in Switzerland ii © ISO 2015 – All rights reserved ISO 12647-5:2015(E) Page Contents Foreword iv Introduction v Scope Normative references Terms and definitions Requirements 4.1.2 Data resolution 4.2 Printing forme requirements 4.2.1 Resolution 4.2.2 Stencil production 4.2.3 Printing forme orientation 4.3 Print production requirements 4.3.1 Visual characteristics of image components 4.3.2 Tolerance for image positioning 4.3.3 Image reproduction Test method and reporting: Control strip Annex A (informative) Process control strip example Annex B (normative) Correction of colorimetric data for variation in substrate colour Annex C (informative) Solid patch aims for various gamut options Bibliography D ata requirements fo r s creen p rinting sys tems D ata delivery I mage s ize to lerance © ISO 2015 – All rights reserved iii ISO 12647-5:2015(E) Foreword ISO (the International Organization for Standardization) is a worldwide federation o f national standards bodies (ISO member bodies) The work o f 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 o f electrotechnical standardization The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part In particular the di fferent approval criteria needed for the di fferent types o f ISO documents should be noted This document was dra fted in accordance with the editorial rules o f the ISO/IEC Directives, Part (see www.iso.org/directives) Attention is drawn to the possibility that some o f the elements o f this document may be the subject o f patent rights ISO shall not be held responsible for identi fying any or all such patent rights Details o f any patent rights identified during the development o f 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 in formation given for the convenience o f users and does not constitute an endorsement For an explanation on the meaning o f ISO specific terms and expressions related to formity assessment, as well as in formation about ISO’s adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary in formation The committee responsible for this document is ISO/TC 130, Graphic technology This second edition cancels and replaces the first edition ( ISO technically revised 12647-5 :2001), which has been ISO 12647 consists o f the following parts, under the general title Graphic technology — Process control for the manufacture of half-tone colour separations, proof and production prints — — — — — — — — iv : Part 1: Parameters and measurement methods Part 2: Offset lithographic processes Part 3: Coldset offset lithography on newsprint Part 4: Publication gravure printing Part 5: Screen printing Part 6: Flexographic printing Part 7: Proofing processes working directly from digital data Part 8: Validation print processes working directly from digital data © ISO 2015 – All rights reserved ISO 12647-5:2015(E) Introduction H i s toric a l ly, th i s I nternationa l Standard e s tabl i she d the pro ce s s control p ara me ters a nd thei r m va lue s for and tolerance s the mo s t i mp or ta nt pro fe s s iona l pri nti ng pro ce s s e s o f the graph ic ar ts i ndu s tr y T he initial concept was that the groundwork for the series was laid down in ISO 12647-1 This part of the I S O 47- s erie s d i ffers from that concep t b e c au s e s cre en pri nti ng h as change d s ign i fic a ntly s i nce th i s I nternationa l Standard was i n itia l ly conceive d T h i s e d ition o f th i s p ar t o f I S O 47 d i ffers cond ition m s from the e arl ier e d ition by no t defi ni ng s p e c i fic pri nti ng but i n s te ad re qu i ri ng th at a s p e c i fic re ference pri nti ng cond ition (ch arac teri z ation data s e t) b e s p e ci fie d T h i s p ar t o f I S O 47 re qu i re s that the colour o f the pri nte d pro duc t match a cha rac teri z ation and s p e ci fie s data s e t or a pri nti ng cond ition m i n i mu m re qui rements and agre e d tolerance s to up on be b y the provider and com mu n ic ate d and the re ceiver pro duce d Where s p e ci fic phys ica l p a rame ters c an i mp ac t the fi na l re s u lt (s c re en a ngle s , re s olution, s cre en me sh , e tc ) , s p e ci fic ation s and tolera nce s are provide d for the s e p a rame ters B e c au s e materi a l pro duce d b y s cre en pri nti ng va rie s widely i n b o th s i z e a nd nom i na l viewi ng d i s tance, a viewing distance metric is introduced as part of all screening and resolution requirements © ISO 2015 – All rights reserved v INTERNATIONAL STANDARD ISO 12647-5:2015(E) Graphic technology — Process control for the manufacture of half-tone colour separations, proof and production prints — Part 5: Screen printing Scope T h i s p ar t o f I S O 47 s p e ci fie s the re qu i rements materi a l us e d for for the s c re en pri nti ng o f fou r- colou r pro ce s s - colou r d i s pl ay, s ignage, and graph ics u s i ng flat b e d or c yl i nder pri nti ng e quipment B o th the s i ze a nd re s olution o f the fi n i s he d pro duc t are u n re s tric te d T he pro ce s s s tage s i nclude d are — d ata prep aration and del iver y, — pro o f pro duc tion, — pri nti ng forme prep aration, a nd — production printing Normative references T he fol lowi ng i nd i s p en s able c u ments , i n whole or i n p ar t, are normatively re ference d i n th i s c u ment a nd are for its appl ic ation For date d re ference s , on ly the e d ition cite d appl ie s For u ndate d re ference s , the late s t e d ition o f the re ference d c u ment (i nclud i ng any amend ments) appl ie s I S O 9, Graphic technology — Prepress digital data exchange — Tag image file format for image technology (TIFF/IT) Graphic technology — Process control for the production ofhalf-tone colour separations, proof and production prints — Part 1: Parameters and measurement methods I S O 47-1 , I S O 47-7, Graphic technology — Process control for the production ofhalf-tone colour separations, proof and production prints — Part 7: Proofing processes working directly from digital data I S O 47- , Graphic technology — Process control for the production ofhalf-tone colour separations, proof and production prints — Part 8: Validation print processes working directly from digital data ISO 13655:2009 Graphic technology — Spectral measurement and colorimetric computation for graphic arts images , Graphic technology — Prepress digital data exchange — Use of PDF — Part 1: Complete exchange using CMYK data (PDF/X-1 and PDF/X-1a) I S O -1 , Terms and definitions For the pu r p o s e s o f th i s c u ment, the term s and defi nition s given i n I S O 47-1 apply © ISO 2015 – All rights reserved ISO 12647-5:2015(E) Requirements 4.1 Data requirements for screen printing systems 4.1.1 Data delivery Screen print systems shall accept digital data delivered as PDF/X data files as defined in ISO 15930-1 or TIFF/IT files as defined in ISO 12639 The intended printing condition shall be either 1) a published Characterized Re ference Printing Condition (CRPC) as listed in the ICC registry at www color.org , or 2) a custom data set where none o f the available re ference colour characterization data sets are considered appropriate for the intended printing because o f the inks, paper, or other factors Where the characterization data to be used have a substrate colour (CIELAB values) that does not match the substrate to be used, the data should be adjusted using the tristimulus correction method defined in Annex B Prior agreement as to the characterization data and substrate adjustment to be used shall be obtained between all parties involved be fore copy preparation work is started Characterization data sets are the only method recognized by this part o f ISO 12647 for the proper identification o f the printing condition to be used Film and/or directly exposed screens shall be generated from digital data and legacy film should be assumed to have been prepared to some agreed upon re ference characterization 4.1.2 Data resolution Input data should be provided at a data spacing o f twice the screen ruling to be used as determined by the scaling criteria, e.g.: 140 cm−1 pixels for a 70 cm−1 screen ruling 4.2 Printing forme requirements 4.2.1 Resolution Printed material produced by screen printing varies widely in both size and nominal viewing distance For screen printing the re ference acceptable image quality criteria shall be based on a 70 cm−1 screen ruling viewed at a distance o f 42 cm (175 lpi at 16,5 inches) This relationship o f distance and screen ruling defines when rosettes are no longer visible to a viewer with 20/20 vision (dot fusion) This relationship should be scaled for other viewing distances or other screen rulings For the same viewing quality at di fferent distances, maintain the relationship o f resolution to distance NOTE For a convenient approximation, divide either the desired distance in meters or the desired resolution in dots per centimetre into 30 to compute the other for that specific pair This is sometimes re ferred to as the rule o f 30 The target resolution shall be based on an agreement between the printer and their customer It should be in accordance with the following three criteria: 1) a minimum screen ruling with dots large enough to reproduce a tonal range from % to 98 % using the mesh as configured, the imaging technique, the emulsion and the ink; 2) a minimum printed dot size that is not less than 1,5x the width o f the thread diameter o f the mesh; 3) a maximum screen ruling as recommended by the “rule o f 30” for the intended viewing condition © ISO 2015 – All rights reserved ISO 12647-5:2015(E) 4.2.2 Stencil production T he s i lver, therma l, or i n kj e t fi l m u s e d for i magi ng s cre en s s l l have s u ffic ient U V den s ity (> 4, 0) i n pri nti ng a re a s a nd s u fficient U V tran s p arenc y (< ,1) required in 4.2.1 be able to produce all dots required in 4.2.1 i n the non-pri nti ng are as to pro duce a l l ts D i re c t to s c re en a nd computer to s cre en s ys tem s (C T S ) sh a l l h ave s u ffic ient re s olution NO TE C omputer to s c re en s ys tem s (C T S ) d i re c tl y i m age the s tenc i l a nd d i re c t to s c re en s ys tem s ( D T S ) app l y an image which is used to create the stencil 4.2.3 Printing forme orientation 4.2.3.1 Printing forme preparation The angle of the screen mesh attached to the screen frame shall be at 0° and 90° ± 1° with respect to the frame The angles of the image shall also be 0° and 90° ± 1° with respect to the frame 4.2.3.2 Screen angles For l f-tone ts without a pri ncip a l a xi s , the nom i na l d i fference b e twe en the s cre en a ngle s magenta, and black sh a l l b e °, with the s c re en a ngle o f yel low s ep arate d at ° from For l f-tone ts with a pri nc ip a l a xi s , the nom i na l d i fference b e twe en s cre en a ngle s and bl ack s l l b e °, with the s c re en a ngle o f yel low s ep arate d by ° from for c yan, ano ther colou r for c yan, magenta, ano ther colou r I n a l l c a s e s , no colou r s hou ld a l ign with i n 7, ° o f the me sh (fra me) I f fle s h tone s are pre s ent, the yel low should not be referenced to magenta NO TE T h i s i s to p re vent moi ré i n fle s h to ne s a nd to en s u re th at no row o f ts l i ne s up with the me s h , wh ich wou ld de s tabi l i z e the s m a l l t s tr uc tu re I t i s p o o r p rac tice to u s e a nd ro tate o ffs e t fi l m s to p ro duce the NO TE It is com mon p rac tice to use fre quenc y mo du l ate d s c re en i n g fo r the yel low for me s ep a ration with ap proxi m atel y the s a me s i z e a s the ts i n the 10 % a re a o f the conventio n a l s ep a ration s a nd a d i fferent to n a l compensation curve 4.2.4 Image size tolerance For fi l m b a s e d s ys tem s , the s e t o f s uppl ie d fi l m s u nder com mon envi ronmenta l e qui l ibriu m sh a l l no t d i ffer b y more tha n , 02 % i n the leng th s o f thei r d i agona l s 4.3 Print production requirements 4.3.1 4.3.1.1 Visual characteristics of image components Visual appearance of the supplied proof Supplied proofs shall be prepared in accordance with either ISO 12647-7 or ISO 12647-8 except where i nd ic ate d b elow and s l l u s e the s a me ch arac teri z ation data s e t cho s en corre c tion fac tor s l l b e u s e d to adj u s t for for pro duc tion T he tri s ti mu lu s the s ub s trate colou r when the pro duc tion s to ck i s no t avai lable P ro o fs s l l h ave the prop er colou r but may h ave a d i fferent s i z e th an the i ntende d pro duc t P ro o f re s olution may b e fi ner th an the i ntende d pro duc t I n th i s c as e the ru le o f sh a l l b e fol lowe d with i n the s trai nts o f the pro o fi ng e qu ipment as s u m i ng the pro o f to b e viewe d at 42 cm 4.3.1.2 Print substrate colour For the b e s t colour repro duc tion, the pri nt s ub s trate colou r s hou ld b e re s tric te d a s s hown i n Table All colou r me a s u rement s l l b e made i n accordance with I S O 5 : 0 9, wh ite b acki ng , M1 NO TE Su r face fi n i s h , i f app l ie d , c a n s e verel y a ffe c t the s ub s trate co lo u r © ISO 2015 – All rights reserved ISO 12647-5:2015(E) Table — Print substrate colour restrictions 90 ≤ 4.3.1.3 L* ≤ 10 −3 ≤ a* ≤ −5 ≤ b* ≤ Ink set colours T he s cre en pri nti ng pro duc tion s l l u s e pro ce s s i n ks wh ich b e s t match the s ol id obj e c tive i n the referenced characteristic data set I f the s e i n ks a re b ei ng u s e d to p ro duce the re qu i re d re ference ch a rac ter i z ation d ata s e t NO TE pr i nt o n l y app l ic atio n s , u s e fo r s c re en Annex C for suggested values for the solids of different gamut classes If these inks are b ei n g u s e d to m atch a n o ffs e t ch a rac teri z atio n d ata, it h a s b e en demo n s trate d th at the s a me i n ks c a n comp l y with ISO 12647-2 goals 4.3.1.4 Ink set gloss I f it i s de eme d ne ce s s ar y to s p e ci fy the glo s s o f s ol id tone colou rs , then the s p e c u l ar glo s s o f the i n k s e t single print solid areas should be measured and recorded at an agreed angle of incidence 4.3.2 Tolerance for image positioning T he ma xi mum devi ation b e twe en the i mage centre s o f a ny two pri nte d colou rs sh a l l no t b e more th an a distance equal to the pitch of the screen ruling used and should not be more than a distance equal to one-half of the pitch of the screen ruling used NO TE T h i s tolera nce i nclude s a ny 4.3.3 for me generatio n de vi atio n s Image reproduction For the pro duc tion pri nt, the ta rge t colou r co ord i nate s o f the s ol id s and two colou r overpri nts sh a l l b e as given i n the s ele c te d charac teri z ation data s e t T he deviation or for from the average o f the pro duc tion ru n sha l l b e as s p e c i fie d i n the s e targe ts va lue s Table colou r s ol id s th roughout the ru n i n pro duc tion i s re s tric te d b y the % o f the pri nts , the colou r d i fference s tolera nce s p e c i fie d i n from for an OK s he e t T he vari abi l ity o f the pro ce s s fol lowi ng cond ition For at le a s t the OK she e t sha l l no t e xce e d the appropri ate vari ation Table and should not exceed one-half of that value All colour measurement shall b e made i n accorda nce with I S O 65 : 0 9, wh ite b acki ng , M1 NO TE T he s e conda r y colou rs re d, gre en , a nd b lue a re dep endent on the pr i nt s e quence a nd can va r y dep end i n g o n cond itio n s th at i nclude the me ch a n ic s o f the p re s s , the s u r face ch a rac ter i s tic s o f the s ub s trate , a nd the rhe olo gic a l a nd tra n s p a renc y pro p er tie s o f the i n ks T hu s , for m a nce o f the p ri m a r ie s to s p e c i fic ation s i s no t s u ffic ient for the co n for m a nce o f the s e conda r ie s T he pro duc tion pri nt s hou ld exh ibit a pre d ic table m idd le tone weight a nd colou r b a la nce (neutra l grey) and should exhibit a predictable tone value transition and balance throughout the colour space NO TE T here a re s evera l me tho d s to ach ieve th i s ob j e c tive S e e I S O/ T S 10 : 0 of the three optional methods and an example of colour balance [2] , , fo r a n a s s e s s ment © ISO 2015 – All rights reserved ISO 12647-5:2015(E) Table — CIELAB Δ Eab tolerances for the solids of the process colours1 Type of tolerance Deviation tolerance Variation tolerance a Black Δ Eab 4,0 1,5 Δ E00 b 2,8 1,1 Cyan Δ Eab 5,0 2,0 Δ E00 b 3,5 1,4 Magenta Δ Eab 6,0 3,0 Δ E00 b 4,2 2,1 Yellow Δ Eab 6,0 3,0 Δ E00 b 4,2 2,1 a The distribution o f CIELAB colour di fferences is not Gaussian but skewed For reasons o f consistency, the variation tolerance is defined here as the upper limit for 68 % o f the production copies This is analogous to a Gaussian distribution where 68 % are within plus or minus one standard deviation of the mean b Tolerance values for DE2000 are given for in formation only Measured in accordance with ISO 13655:2009, M1 with white backing Test method and reporting: Control strip For process control a multi-colour control strip shall be used This control strip shall be printed along with the subject on all proo fs and should be printed on all production jobs It shall contain well-defined control patches with accurate tone value designations and meet the quality and resolution requirements o f the accompanying image The screen print colour bar shall include Solid; C, M, Y, K patches; Tonal percentages o f C, M, Y, K o f %, 10 %, 25 %, 50 %, 75 %, and 90 %; RGB overprints a white patch; and neutral grey C,M,Y patches for 10 %, 25 %, 50 %, 75 %, and 90 % (see Annex A) The control patches on the stencil, together with the subject matter, should be inspected to ensure that the intended tone values have been achieved In addition, for in formation purposes, or the checking o f stencil and flooding problems, hal f-tone control patches may be printed along with the control strip that contain the same half-tone screen values as used in the image area of the print NOTE The effective measurement aperture diameters of the densitometers on the print need to be large enough to accommodate and include the required quantity o f hal f-tone dots in each measurement as specified in the documentation o f the densitometers’ manu facturer In addition, for measurement with apertures o f less than mm diameters the typical practice is to average five readings o f every control patch For line screens 18 dots per centimeter or less it is recommended that an average o f five or more readings in every control patch and the measurement should then be averaged © ISO 2015 – All rights reserved ISO 12647-5:2015(E) Annex A (informative) Process control strip example Figure A.1 — Example IDEAlliance Screen control strip © ISO 2015 – All rights reserved ISO 12647-5:2015(E) Annex B (normative) Correction of colorimetric data for variation in substrate colour Although there are a number of computational techniques used or proposed for the correction of colorimetric data for variation in substrate colour, the consistent use o f a single method enhances the ability o f di fferent users to achieve similar results One conversion method that produces reasonable results for hal f-tone type images is based on the observation that when the differences in CIE X, CIE Y, and CIE Z between measurements made of identical patches on two substrates having different colours are plotted versus the CIE X, CIE Y, and CIE Z respectively, for measurements on substrate versus substrate 2, the result is approximately a straight line This leads to a model for predicting the colour of a print on substrate in the form of a linear conversion Formulae (B.1) and (B.2) show the predictive conversion for CIE tristimulus X for predicting the colour change between substrate and substrate NOTE The approximate linear relationship fits best when the absorbance o f the two substrates are similar For CIE X: X2 = X1 × ( + C ) − Xmin × C (B.1) with C= where X s − X s1 X s1 − X X2 is the measured value of X of the specimen on substrate 1; is the converted value of X of the specimen on substrate 2; C is a constant; X1 (B.2) is the measured value of X of substrate 1; Xs2 is the measured value of X o f substrate 2; Xmin is the minimum value of X of the specimen on substrate Xs1 NOTE In practice, the X, Y, and Z values of the four-colour solid are often used as an approximation of the minimum values Conversion of CIE Y and CIE Z is accomplished in an analogous manner and new CIE L*, a *, and b * CIELAB values are computed This colorimetric conversion method is referred to as the tristimulus correction method NOTE This is similar to, but not necessarily identical to the International Color Consortium method re ferred to as substrate relative colorimetric transforms © ISO 2015 – All rights reserved ISO 12647-5:2015(E) Annex C (informative) Solid patch aims for various gamut options Table C.1 — CIELAB colour values for solid tones of the primary and secondary colours for screen printing Small gamut option Black (K) Cyan (C) Magenta (M) Yellow (Y) Reda (M + Y) Greena (C + Y) Blue a (C + M) a b L* 24 59 51 90 50 55 28 a* b* −35 −43 −15 70 −11 59 −68 27 Colour sequence Yellow, Cyan, Magenta According approximately to o ffset PC1 66 42 32 −41 Medium gamut option b L* 18 52 47 89 47 49 21 a* b* −33 −51 −5 74 −9 67 −65 26 83 50 30 −40 Large gamut option L* 46 42 88 44 43 16 a* b* −32 −54 79 −7 66 −62 29 10 100 47 28 −39 © ISO 2015 – All rights reserved ISO 12647-5:2015(E) Bibliography [1] ISO -3 : 0 9, conditions Photography and graphic technology — Density measurements — Part 3: Spectral Graphic technology — Methods of adjustment of the colour reproduction of a printing system to match a set of characterization data [2 ] I S O/ T S 1 : 0 9, [3 ] I S O 7- : 0 , [4] I S O 47-2 , Graphic technology — Vocabulary — Part 3: Printing terms Graphic technology — Process control for the production ofhalf-tone colour separations, proof and production prints — Part 2: Offset lithographic processes © ISO 2015 – All rights reserved ISO 647-5 : 01 (E) ICS 37.100.01 Price based on pages © ISO 2015 – All rights reserved