ISO 12647/ Printing Standards Test Day

Transcription

1 BPIF Technical Committee July th 6 Heidleberg UK ISO 167/- Printing Standards Test Day Report collated by Paul Sherfield The Missing Horse Consultancy Ltd

2 Contents Page 1 Introduction - Peter Arnel: Chairman, BPIF Technical Standards Committee 3 Aims of the test day 3 Executive summary 5 Background - Paul Sherfield 6 5 Methodology 7 6 PressView report - Eric Koldenhof 9 7 GRACoL G7 report - Dan Wilson 15 8 Mellow Colour report - Alan Dresch 19 9 Proof Control report - Paul Sherfield 5 1 Acknowledgements 9

3 1 Introduction Introduction During the last year, as print management companies have taken a stronger hold on the sheet fed print market, sheet fed printers in the UK have suddenly had to take printing to an international colour standard seriously. The question though is which (or who s) standard. This question is what prompted me to instigate this project. As printers we need clear guidance for our process controls to be effective. It is not up to us to set the standard, but we need to be involved so that the standard (and we need only one standard) is clear, achievable and sustainable. Those that look for ISO to provide this standard will be disappointed, it is not clear and certainly does not provide the one standard that we need. At the moment there are really two standards in practice (although some see them as methods to achieve the ISO 167 standard). Fogra, which is the more established one, developed by the German print industry it is based on ISO, but unlike ISO defines the dot gain regardless of screen ruling (the dot gain it uses is the same as a lot of us use anyway so it is more in keeping with the UK style of printing). GraCol is the American system. They use the same process colours as Fogra and ISO but adjust the dot gain for CMY to match a defined grey throughout the tonal range. Once this has been established they concentrate on controlling the grey balance throughout the run. GraCol are marketing this very aggressively in the US and Far East and accrediting printers as Master Printers when they have achieved the standard. The purpose of the test was to see how both Fogra and GraCol were implemented and compare the results. I will leave others later in the report to give their views on the results... Finally I must thank Paul Sherfield for all his help, patience and considerable time he spent on the project, Dan Wilson for his time and enlightening GraCol presentation, the BPIF for organising the day and all at Heidelberg UK who provided the resources for us to carry out the test. The reports and observations contained in this report are those of the experts who took part in the test day, and do not necessarily represent the views or policy of the BPIF Technical Standards Committee or those of the BPIF itself. What ever the conclusions to be drawn from the test day I hope this project sends a clear message to others that the BPIF wants to be involved and to contribute to setting standards for our industry. Peter Arnel Chairman BPIF Technical Committee August 6 3

4 Aims of the test day Aims of the test day To launch the newly established BPIF Technical Standards Committee, chaired by Peter Arnel (White Horse Press, Newbury). To encourage the use of the ISO 167/- printing standard in the UK. To compare in a very hands on way the Fogra and G7 methods of process controlling prepress presses to this standard. To assess what this would mean to clients: designers, publishers, corporates etc., who need to print across borders without issues of colour when supplying images and pages.

5 3 Executive summary Executive summary The GraCol G7 and Fogra methods of process controlling presses to the ISO 167/- standard were compared and tested on July at Heidelberg UK s Brentford showrooms at a test day organised by the BPIF Technical Standards Committee. A standard linear test forme was printed to the ISO paper type 1 L a b colour values and from these sheets, correction curves were calculated using both methods. The GraCol G7 method is based on Neutral Print Density Curves, Fogra s on TVI (Dot Gain). After this the curves were validated by making plates from the standard test forme to both correction curves and methods. Then further Visual test forme was plated to using methods of compensation, i.e. two further sets of plates. This visual test forme had the 5 colour images from the Altonia Test Suite visual forme, separated to two Fogra/ISO data set 7 profiles, the current Sheet fed standard for coated papers, a beta Fogra 39 dataset profile reflecting the forthcoming change to the standard and a beta G7 profile from data from their last press tests. Both sets of plates were printed. The general consensus was that there was only a small difference in the visual appearance between all 8 versions of the images. Both method of process control give good results. A G7 separated image, printed on a press set up to Fogra 7 data TVI will reproduce acceptably for most markets. A Fogra 7 separated image, printed on a press set up by G7 s Neutral Print Density method will also print acceptably for most markets. Also the beta Fogra 39 separations were acceptable under both conditions. It should be noted that two companies attending the day, working in the fine art area of printing commented that the small differences in visual appearance would not be acceptable to their marketplace and clients. 5

6 Background Background This started as a small idea from Peter Arnel and Paul Sherfield. They were originally going to invite a few people and use the G7 How to document themselves, so were delighted when Dan Wilson, an accredited G7 expert, offered his services. Numbers then escalated as it was publicised: over 5 people attended The IDEAlliance GraCoLG7 team, Don Hutchinson and others, were very helpful during a conference call Dan Wilson and Paul Sherfield had with them, a real print across borders 5 minutes. Dan provided the UK printing industry with an excellent overview and practical demonstration of the G7 method. The day was real world demo. In 6 hours, 8 sets of plates and make-readies were carried out. This was not a standardssetting press run. In the time we had the press was process controlled into Fogra 7 and G7 reasonably well, the demonstrations of the methods were as important as the results. 6

7 5 Methodology Methodology We started with a linear test forme with G7 and Fogra elements, plus images from the Altona Visual Suite separated to Fogra 7 and a G7 beta profile, using device link profiles generated using Alwan Color Expertise s ColorHub software. It was printed to the Fogra 7 CMYK Lab values: From this forme, illustrated above, the press was process controlled using both the Fogra and G7 methods, TVI (Dot gain) and NPDC (Neutral print density curves). We used for this Heidelberg s Image Control, Eric Koldenhof s PressView software, a Gretag Macbeth SpectroEye and the IDEALink Curve G7 software with a X-Rite DTP 7. Two new sets of plates, one based on amended TVI curves, the Fogra method, the other based on G7 s NPDC were made and printed to validate the correction curves. 7

8 Methodology 5 Then from a visual test forme, illustrated above, containing the 5 Altona test images, separated again using device link profiles generated using Alwan s ColorHub software, to: ECI ISO coated Adobe Fogra 7 G7 beta dataset Fogra 39 beta We then made two more sets of plates to the G7 and Fogra curves and printed both to the Fogra data set 7 Lab CMYK values. The general consensus was that there were small differences between the 8 sets of images printed from the calibrations, but for most work, it would be acceptable. There were a few exceptions to this view from people and companies working at the very high-end of the quality market in the UK. The grey balance of the sheets, the Fogra grey balance, after calibration, based on 5%C, 36%M, 33%Y was: De average for K over the sheet (5 samples) 1. CMY grey L 6.1 a.6 b -3.3 from top bar De average for CMY grey over the sheet (5 samples). For the G7 sheet based on 5%C %M %Y: 5% K L 61.9 a -. b-.8 from top bar De average for K over the sheet (5 samples) 1. CMY grey L 58. a 1.8 b.7 from top bar De average for CMY grey over the sheet (5 samples).9 We believe we achieved our aims for the day, it was not a standards test run, but a practical demonstration of the power of standard printing conditions, process control and their implementation as the final link in the colourmanaged page and image workflow. 5% K L 6. a -.1 b -.9 from top bar 8

9 6 Press View report PressView report This section contains Eric Koldenhof s observations on the day and the tests Eric runs a colour management consultancy in The Netherlands, Koldenhof Graphics Expertise, and has developed the PressView software to control and validate presses to ISO 167/- standard printing conditions. We were very pleased that Eric (and his software) could join us in this exercise. Printing Across Borders - UK Print test FOGRA 7L - GraCol G7 comparison Client: Printing Across Borders Author: Koldenhof Graphics Expertise Erik Koldenhof Date: :1:9 Contents Introduction Measurement details Disclaimer 9

10 Press View report 6 Introduction This document is for informational purposes only. About the PressView interface. PressView main interface does not provide you all the numbers, and it is not mentioned to be. It should be understandable for everybody, our detail detail-pages do have all the numbers you need. The CIE CIE-ab is drawn in white (reference) and blue (measured sample). The Brightness is CIE CIE-L, were '' is the reference aim for L* and the difference is drawn in the printed color. Also the function is inverted, if you are above target, the color is too dark. Dotgain (spectral based TVI) is also based on the reference '' (actual value depending on the reference) and the difference is drawn. Please note that the densities shown in the upper right corner are measured with the EyeOne (Status Status-E, No POL filter) are for informational purposes only and should not be compared to Polarised densities. Target densities used in the G7 approach are based upon the results from the first '7L' sheets. Graybalance is drawn for highlight (%), midtone (%) and shadows (8%) Every tiny circle around the centre is about 1 Delta Delta-E color difference. Please note that the centre of the diagram is not intended to be 'neutral gray'. It is again your target gray balance, no matter how it is defined. For our Pressview strip, we took a former set of Fogra Graybalance CMY values, and calculated the absolute CIE CIE-Lab co co-ordinates via the reference ICC profile (in this case ISOcoated.icc). Therefore, no matter what which defined GrayBalance you are using, you always target for the centre. In the examples shown, if everything is '' then you are printing exactly the same as FOGRA 7L. 7L test After the final CTP compensation these were the results. The white color gamut is FOGRA 7L (with an edited Cyan solid to match ISO more closely), the blue is the actual printed result (wet condition). Brightness and dotgain are showed as difference between FOGRA 7L (reference) and the actual print (sample). We still measured a reddish cash in Graybalance, which is particular visible in the shadow areas. We did not have the time to examine and/or correct the cast (probably CTP curve fine finetuning). G7 test The results are based upon the densities derived from the 7L test, but plates were adjusted via the G7 Neutral Gray method and software. With these calibrated plates the print print-run was made again, under the same circumstances as the 7L test. 7L 7L-G7 comparison Please keep in mind that these are the results from one single test today at Heidelberg UK. The results from the 7L test (image no.1) were saved as reference (now drawn in white). G7 results are drawn in blue, as the sample. The color gamut remains the same as we did not change the inks, densities or color sequence. Graybalance behaviour as actually more or less comparable to our 7L test (between 1 and Delta Delta-E from each other). The only difference is of course the actual dotgain. We targeted the 7L test towards 13% TVI, although we were using a Lpi screen. The G7 calibration did not calculate for a 'desired' dotgain. Therefore, it is not so strange that this comparison results in a % higher dotgain in the G7 testrun. 1

11 6 Press View Report Measurement details Client: Koldenhof Graphics Expertise Reference: ISO167- PT1/ (e) Base Dmax (KCMY): Device: Pab Speedmaster Sample: Pab Print test G7cal Prod Dmax (KCMY): Y M+Y C+Y,1 5, 6,7 M C C+M Highlight Midtone Shadow Reference (dry) Sample (wet) PressView 1v3. Copyright 6 Colorware bv. 3,3,7 1,3 1,7 1,9,7 6,3 All rights reserved. Alle rechten voorbehouden. Sample Reference Status E L a b L a b OK. Paper Paper OK 3.3 Black Black OK.7 Cyan Cyan OK 1.3 Magenta Magenta OK 1.7 Yellow Yellow OK 1.9 Red Red OK.7 Green Green ERROR 6.3 Blue Blue Dotgain (spectral measured TVI) Black Cyaan Magenta Yellow Sample Reference Difference Generic information Job nr. Name Description Date Remarks PAB Pab Print test G7cal PT1 G7 cal nr :6:6 - Flow change Printed on Reading ISO papertype 1 Wet 1 Screen Reference name Reference description 15 ISO167- PT1/ (e) ISOcoated (fogra_7l) Production data Base densities (KCMY, Spot 1, spot ) Water percentage (KCMY, Spot 1, Spot ) Production densities (KCMY, Spot 1, Spot ) Paper thickness Pressure fine (KCMY, Spot 1, Spot ) Press data Inks: Black Cyan Magenta Yellow Spot 1 Spot HST Resista Eco 1F HST Resista Eco HST Resista Eco HST Resista Eco - - Setup: Blanket thickness Alcohol percentage Hdm premier Fountain solution Water temperature Conductivity Hdm Saphira soft

12 Press View Report 6 Client: Koldenhof Graphics Expertise Reference: ISO167- PT1/ (e) Base Dmax (KCMY): Device: Pab Speedmaster Sample: Pab Print test COMP Prod Dmax (KCMY): Y M+Y C+Y M C C+M Highlight Midtone Shadow Reference (dry) Sample (wet) PressView 1v3. Copyright 6 Colorware bv. 3,3,7 1, 1,9 1,9 1,7 5,6 1,8 All rights reserved. Alle rechten voorbehouden. Sample Reference Status E L a b L a b OK 1.8 Paper Paper OK 3.3 Black Black OK.7 Cyan Cyan OK 1. Magenta Magenta OK 1.9 Yellow Yellow OK 1.9 Red Red OK 1.7 Green Green ERROR 5.6 Blue Blue Dotgain (spectral measured TVI) Black Cyaan Magenta Yellow Sample Reference Difference Generic information Job nr. Name Description Date Remarks PAB Pab Print test COMP PT1 FOGRA 7L compensated (nd) :7:38 - Flow change Printed on Reading ISO papertype Wet 1 Screen Reference name Reference description 15 ISO167- PT1/ (e) ISOcoated (fogra_7l) Production data Base densities (KCMY, Spot 1, spot ) Water percentage (KCMY, Spot 1, Spot ) Production densities (KCMY, Spot 1, Spot ) Paper thickness Pressure fine (KCMY, Spot 1, Spot ) Press data Inks: Black Cyan Magenta Yellow Spot 1 Spot HST Resista Eco 1F HST Resista Eco HST Resista Eco HST Resista Eco - - Setup: Blanket thickness Alcohol percentage Hdm premier Fountain solution Water temperature Conductivity Hdm Saphira soft

13 6 Press View report Client: Koldenhof Graphics Expertise Reference: Pab Print test COMP Base Dmax (KCMY): Device: Pab Speedmaster Sample: Pab Print test 7L - G7cal Prod Dmax (KCMY): Y M+Y C+Y,1, M C C+M Highlight Midtone Shadow Reference (wet) Sample (wet) PressView 1v3. Copyright 6 Colorware bv.,,,9,7,6 1,7,3 All rights reserved. Alle rechten voorbehouden. Sample Reference Status E L a b L a b OK.3 Paper Paper OK. Black Black OK. Cyan Cyan OK.9 Magenta Magenta OK.7 Yellow Yellow OK.6 Red Red OK 1. Green Green OK.7 Blue Blue Dotgain (spectral measured TVI) Black Cyaan Magenta Yellow Sample Reference Difference Generic information Job nr. Name Description Date Remarks PAB Pab Print test 7L - G7cal PT1 comparison :5:57 - Flow change Printed on Reading ISO papertype Wet 1 Screen Reference name Reference description 15 Pab Print test COMP PT1 FOGRA 7L compensated (nd) Production data Base densities (KCMY, Spot 1, spot ) Water percentage (KCMY, Spot 1, Spot ) Production densities (KCMY, Spot 1, Spot ) Paper thickness Pressure fine (KCMY, Spot 1, Spot ) Press data Inks: Black Cyan Magenta Yellow Spot 1 Spot HST Resista Eco 1F HST Resista Eco HST Resista Eco HST Resista Eco - - Setup: Blanket thickness Alcohol percentage Hdm premier Fountain solution Water temperature Conductivity Hdm Saphira soft

14 Press View report 6 Disclaimer Copyright No part of this publication may be reproduced, transmitted, transcribed, stored in a retrieval system, or translated into any language in any form by any means without the written permission of Koldenhof Graphics Expertise. Liability This material is provided for informational purposes only; Koldenhof Graphics Expertise has tried to ensure that the information in this report is correct but assumes no liability related to it s use, errors and omissions. In no event shall Koldenhof Graphics Expertise be liable for any damages whatsoever including, without limitation, damages for loss of business profits, business interruption, loss of business information, or other pecuniary loss or incidental or consequential damages, arising out of the use of -or inability to use use- this information, even if Koldenhof Grafimedia Expertise has been advised of possibility of such damages; or for any claim by any other party under any legal or equitable theory. Content is subject to change without notice. July 6. 1

15 7 GraCol G7 report GraCol G7 report The section is the report from Dan Wilson, our G7 expert for the day, and speaks for itself. BPIF ISO/GRACoL Print Run As told by Dan Wilson of Prepress I.T. Limited The information I offer here is my own opinion; I do not speak for, or represent (or paid by) any other person or organization. I offer this report in good spirit and hope that this contributes to healthy debate in the Industry. Hi, I am Dan Wilson and my small Dublin based consulting business is called Prepress I.T. Limited ( Having moved to Dublin from Australia in March this year, I remain a Committee member of the Lithographic Institute of Australia (NSW Branch) and currently serve as their European Correspondent. As well as consulting work in Ireland/EU, U.K. and Australia from my base in Dublin, I hope to broaden international Industry contacts for the Trade and Associations in Australia. Last November I gave a presentation on International Print Standards at the LIA s Biennial conference in Sydney, just the information and not an opinion piece. Quite a few people connected to ISO in Europe, U.K. and the U.S. along with IDEAlliance offered me a lot of help and introductions during my research over the last years. Thank you all for your generous help. There is passionate support for published ISO standards in many parts of the world. However, a lot of countries do not participate or observe the work of the TC13 Committee (last month I presented information in Sydney with a view to encouraging the Industry in Australia to take-up observer status to the TC13 s work). During my research on international print standards, I happened upon the work being done by the GRACoL 7 Committee. I liked being able to download the How To and did my first G7 (Beta) calibration last December using the graph paper method. Other things I like about G7 is that when using the correct paper, ink, printing sequence, etc., the output is an implementation of ISO 167- and there is a very big market for printing to that standard. The benefit that really made me a fan of G7 is that in a site where they are not selling ISO 167 compliance to their customers, a printer now has the ability to implement a process that will take into account every variable in his factory (non ISO ink, different colour paper, different ink sequence, poor but consistent equipment, etc.) and produce fairly good quality printing that has a simple quality control practice using a densitometer. While the prints might not match ISO 167- perfectly, this printer will be producing a better product if they are doing things like not using the correct sequence for whatever reason they would never match the standard anyway. G7 press calibration combined with G7 calibrated proofs greatly reduces the opportunity for customers to reject a job or seek discounts. Indeed as the G7 calibration is to a defined L*a*b* grey value the results from this plant will not look a million miles different to that from site set up to use the ISO control variables (with the notable exceptions of secondary overprint colours). As the G7 method and the Neutral Print Density Curve offer a close visual match between different printing processes (due to calibrating to an L*a*b* grey target), I think it is an ideal method for plants with sheet fed and web presses especially if they generate their own proofs. I recently attended the GRACoL Experts course in Michigan and am now qualified to implement and train a company with the G7 process and can also qualify a printer as an "IDEAlliance Master Printer". 15

16 GraCol G7 report 7 BPIF/Heidelberg Print Test Day Firstly, I wish to thank the BPIF, Paul Sherfield, Peter Arnel, Heidelberg, X-rite and Koldenhof Graphics Expertise for binging all the equipment and great venue together for this most interesting series of print runs. It was a very busy and enjoyable day for me. While I am pleased with, and stand by the result of the day, there were few things I would have preferred to do but time did not permit: G7 Calibrate the GMG/Epson proofer. Explore soft proofing set-ups Have more than 1 minutes to understand the Prepress/RIP set up. There was a minor rounding error to the values I wanted not dramatic but I would have liked the time to solve it to make things perfect. Collect density, L*a*b* and dot gain readings from every job we ran. Run the calibration job after correction on the uncoated stock. Stand at the press console to personally confirm every detail was correct and maybe even push the buttons on the press! Late News Some days after the BPIF print run, I discovered there were incorrect values in the GRACoL PP3XN reference file used with the X-Rite DTP7 (the PP3XN chart is used to derive G7 calibration data). This error would have put a yellow cast of % to 5% over the entire job, most noticeable in the grey areas. A colleague discovered it on press during a G7 calibration. He thought to compensate on press the D/Max of the yellow unit would need to be reduced to about.9. The erroneous reference file has been corrected. Job sequence for the day 1 Calibration forme printed to ISO standard density Coated Type 1 Calibration forme printed to ISO standard density Uncoated Type 3 3 Calibration verification forme Fogra 7L Coated Type 1 Calibration verification forme G7 Coated Type 1 5 Calibrated images forme Fogra 7L Coated Type 1 6 Calibrated Images forme G7 Coated Type 1 7 G7 Images forme (as above) printed to Uncoated Type 3 ink density 8 Calibrated Images forme G7 Uncoated Type 3 (data from run #) Ironically, not one job we did was within the ISO specification as we printed lpi screen rather than 15lpi. Being a real world situation, that did not really matter. Between Job # and #3 I gave a one-hour PowerPoint presentation on IDEAlliance, GRACoL and the G7 calibration methodology. My analysis detailed on the following pages is derived from using a non-uv EyeOne on dry prints; unfortunately I did not have a densitometer available to me this week. Coated Type 1 paper observations (Jobs #1,3,,5,6) Using ISO certified/compliant ink on Type 1 paper the press was run to standard density with the solid patches read using a Spectro to ensure correct L*a*b* values were achieved. Job #1: Type 1 Coated Paper Calibration forme that was used to calibrate both methods included targets to measure density, dot gain and included the GRACoL gray finder target along with the PP3xn target. The PP3xn target includes a series of c,m,y and k patches at various densities this data is used to calibrate the NPDC (Neutral Print Density Curve) used by the G7 process. 16

17 7 GraCol G7 report Job #3: Type 1 Coated Paper FOGRA 7L corrected Calibration forme was printed again to confirm RIP adjustments were in line with expectations. Job #: Type 1 Coated Paper G7 corrected Calibration forme was printed again to confirm RIP adjustments were in line with expectations. The results were quite close to those expected, however the printer mentioned that it was possible the density was down a little on this print run. Unfortunately, I was elsewhere generating the correction curve data for the uncoated stock and could not supervise as closely as I would have preferred. Regardless, the result was very close to where I wanted it. Job #5: Type 1 Coated Paper FOGRA 7L corrected Images forme was printed to ascertain what differences would be apparent for legacy images separated into Fogra 7 (Adobe) and ISO coated (ECI) cmyk colour space. The images were also separated into ISO Fogra 39 beta and GRACoL Beta cmyk colour spaces. The latter colour spaces being beta versions do not necessarily indicate what the final profiles will look like. Job #6: Type 1 Coated Paper G7 corrected Images forme was printed to same density target as job #5; the content of the forme was identical to Job #5. The most important and relevant comparison is using the legacy images separated into Fogra 7 (Adobe) and ISO coated (ECI) cmyk colour space and putting this part of the forme next to the same images on job #5. Uncoated Type 3 paper observations (Jobs #,7,8) Job #: Type 3 Uncoated Paper The same calibration forme as Job #1 was used. We printed to ISO densities specified for Type 3 paper. This job included targets to measure density, dot gain and included the GRACoL gray finder target along with the PP3xn target. The PP3xn target includes a series of c,m,y and k patches at various densities this data is used to calibrate the NPDC (Neutral Print Density Curve) used by the G7 process. Job #7: Type 3 Uncoated Paper Using the same G7 plates calibrated for the Type 1 Coated paper, I asked the printer to reduce the ink density to that specified for Type 3 paper. I did this because I was interested to see what would happen. The result is a very agreeable print with good colour balance. Job #8: Type 3 Uncoated Paper This job used new plates G7 calibrated from data gathered on Job #. Again, this job produced very good colour but was a touch warm in comparison to the other print jobs. Unfortunately time did not permit printing the calibration forme to confirm the settings were correctly adjusted. As mentioned previously, the two other colour spaces are still beta they are interesting but not a stake in the ground and may be changed before any official release. 17

18 GraCol G7 report 7 Analysis Although time did not permit running the corrected calibration plate, the images plates was run for all jobs. There was one useful reference point on all the images sheets - the 5K and 5,, patches. Job # Coated Type 1 Paper - G7 calibrated print run. The following paper included reference values were displayed in IDEALink Curve. Predicted Achieved 5,,... L* 55.6 L* K... L* 58.5 L* 61.6 This indicates the k was printing a little light (as mentioned in notes regarding Job #. The above values can also be expressed as in Density readings. Running correct ink densities, a printer could reliably use a densitometer set to minus paper and read the values below from two targets to know that target cmyk densities had been achieved. 5,,... D.51 5K... D.7 Most printers use their densitometer set to include paper the revised predicted target would be: 5,,... D.59 5K... D.55 Using the G7 Uncoated Calibration in Job #8, the paper included reference values generated by the IDEALink Curve software. Predicted Achieved 5,,... L* 57.6 L* 59. 5K... L* 59.9 L* 58.3 Summary In the pressure cooker of the day we sacrificed printing confirmation of calibrations and did not have a second bite on the RIP settings where an adjustment of 1 or % would have made the result just that little bit sweeter. While there is How To Version 6_Final available for download on the GRACoL web site, which shows how to achieve the G7 calibration by drawing graphs manually, I use the IDEALink Curve software to achieve the same result a much quicker method. In the question and answer session at the end of the day a large part of the focus was asking me what dot gain adjustment did you do? To reiterate, the G7 method is focussed on generating a cmy and k balance to a defined L*a*b* grey target (the Neutral Print Density Curve). The changes in RIP tone values are focussed on this target without regard to trying to match a dot gain (TVI) curve. Yes, the dot sizes get changed to achieve this balance, but in the G7 method Dot Gain has secondary importance and is used as a reference point after the calibration process to ensure the health of the press and production process. During the final Question and Answer session comments were along the lines of there is not very much difference, this shows the G7 method is an implementation of ISO 167-, Comparing FOGRA to G7, you would see this type of variation in a normal print run. I even recall someone mentioning the G7 prints looked too yellow. Equally, there were some present that said they preferred the FOGRA calibration and would not be prepared to look at alternatives. Thanks again to all who contributed and attended, finally mention should also be made of the positive contribution the Printing Across Borders forum affords the Industry globally. Dan Wilson Dublin, Ireland Ph: +353 () dan.wilson@prepress-it.com.au 18

19 8 Mellow Colour report Mellow Colour report Alan Dresch, who runs Mellow Colour, is one of the UK s leading expects on standard printing conditions, press process control methods and ISO 167/-. Due to commitments he was unable to join us on the day, but has prepared his own reports using his own software, PrintSpec, from the sheets printed on the day. Alan writes: What follows are three PrintSpec Summary sheets and two PrintSpec Gradation sheets made from the ISO7 and G7 prints. There are two G7 Summary reports - identical, except one has Curve A selected as the target and the other Curve B, I produced two so that we could compare the G7 curve with both target curves. Also attached are two Gradation sheets from the G7 and ISO 7L PrintSpec reports. I generated the reports from elements just below the Altona Flesh tone image. All of these PrintSpec reports use the targets from ISO 167- (Black Backing). The PressView report that you have seems to use different measurement conditions and FOGRA7L press run measurement data as the targets. My visual assessment of the results is that the G7 print has a little less Sparkle or Gradation through the middle tones, this can be seen in the gradation reports attached if you compare the angle or slope through the 5% point on each chart. This can be explained very easily of course - the G7 curve is more symmetrical having a higher density at the 5% point compared with curve A which has a (European) positive film heritage where the 5% dots got smaller compared with traditional negative working US platemaking methods which made the 5% dots get bigger. With G7 separation the results should be the same of course from the Sparkle point of view. I like the more symmetrical G7 curve to be honest as it is more typical of how a printing press works from a linear plate. I m not convinced about creating TVI compensation curves from grey balance ramps because it could mask printing machine and consumables problems that would need to be addressed if a stable process is the goal. The reports are fairly self-explanatory I think. I would hazard a guess that the Yellow has been run heavy for both prints in an attempt to match the ISO targets, but this is not possible as the paper contains a lot of optical brightener. The blue hue of the paper fails the ISO target on the b* axis making it impossible to achieve a very low DeltaE Yellow. 19

20 Mellow Colour report 8 PrintSpec? Gradation Click on charts to enlarge and reduce % % % 6% 8% 1% % % % 6% 8% 1% % % % 6% 8% 1% % % % 6% 8% 1% Vertical axis - Density: ISO 5-3 Unpolarised -6 Mellow Colour - ISO 7 Gradation

21 8 Mellow Colour report PrintSpec? Gradation Click on charts to enlarge and reduce % % % 6% 8% 1% % % % 6% 8% 1% % % % 6% 8% 1% % % % 6% 8% 1% Vertical axis - Density: ISO 5-3 Unpolarised -6 Mellow Colour - G7 Gradation 1

22 Mellow Colour report 8 PrintSpec Summary BPIF_Tests_ISOCurve Heidelberg 7 Front Magno Gloss115 - Stehlin Reflecta Screen 31 Jul 6 13:59 ISO Offset Litho Paper Type 1 ISO Curve A ISO 5-3, D5, Unpolarised, Black backing a % 18% 16% 1% 1% 1% 8% 6% % % Click on a chart to see more detail. Ink Colour b Dot Gain (Tone Value Increase) % % 5% 5% 75% 1% Grey Balance Print Light Grey Mid Grey Dark Grey White Obligatory Tolerance Sample print Paper L* a* b* L* a* b* White ±3 ± ± Solid Ink Colour Cyan Magenta Yellow Black Overprints Red Green Violet 3Colour Target Sample print Dot Gain 5% 5% 75% 5% 5% 75% Cyan Magenta Yellow Black Informative House Paper L* a* b* L* a* b* White ±3 ± ± Solid Ink Density Cyan Magenta Yellow Black 5% Ink Density Cyan Magenta Yellow Black Relative Grey Light Grey Mid Grey Dark Grey KEY ISO Specification Tolerance E L*a*b* Tolerance E a*b*... Obligatory Out of tolerance - Red In tolerance - Green Informative Optional Out of tolerance - Orange In tolerance - Green N/A 1. N/A 11.5 N/A 9. N/A N/A Target ISO 5-3 Sample print E L*a*b* Sample print ISO Target Sample print ISO 5-3 ISO Sample print E a*b* Example Example Example Example -6 Mellow Colour -

23 8 Mellow Colour report PrintSpec Summary BPIF_Tests_G7_Cal Heidelberg 7 Front Magno Gloss115 - Stehlin Reflecta Screen 31 Jul 6 13:5 ISO Offset Litho Paper Type 1 ISO Curve A ISO 5-3, D5, Unpolarised, Black backing a 5% % 15% 1% 5% Click on a chart to see more detail. Ink Colour b Dot Gain (Tone Value Increase) % % 5% 5% 75% 1% Grey Balance Print Light Grey Mid Grey Dark Grey White Obligatory Tolerance Sample print Paper L* a* b* L* a* b* White ±3 ± ± Solid Ink Colour Cyan Magenta Yellow Black Overprints Red Green Violet 3Colour Target Sample print Dot Gain 5% 5% 75% 5% 5% 75% Cyan Magenta Yellow Black Informative House Paper L* a* b* L* a* b* White ±3 ± ± Solid Ink Density Cyan Magenta Yellow Black 5% Ink Density Cyan Magenta Yellow Black Relative Grey Light Grey Mid Grey Dark Grey KEY ISO Specification Tolerance E L*a*b* Tolerance E a*b*... Obligatory Out of tolerance - Red In tolerance - Green Informative Optional Out of tolerance - Orange In tolerance - Green N/A 11. N/A 11.8 N/A 8.3 N/A N/A Target ISO 5-3 Sample print E L*a*b* Sample print ISO Target Sample print ISO 5-3 ISO Sample print E a*b* Example Example Example Example -6 Mellow Colour - 3

24 Mellow Colour report 8 PrintSpec Summary BPIF_Tests_G7_Cal Heidelberg 7 Front Magno Gloss115 - Stehlin Reflecta Screen 31 Jul 6 13:5 ISO Offset Litho Paper Type 1 ISO Curve B ISO 5-3, D5, Unpolarised, Black backing a 5% % 15% 1% 5% Click on a chart to see more detail. Ink Colour b Dot Gain (Tone Value Increase) % % 5% 5% 75% 1% Grey Balance Print Light Grey Mid Grey Dark Grey White Obligatory Tolerance Sample print Paper L* a* b* L* a* b* White ±3 ± ± Solid Ink Colour Cyan Magenta Yellow Black Overprints Red Green Violet 3Colour Target Sample print Dot Gain 5% 5% 75% 5% 5% 75% Cyan Magenta Yellow Black Informative House Paper L* a* b* L* a* b* White ±3 ± ± Solid Ink Density Cyan Magenta Yellow Black 5% Ink Density Cyan Magenta Yellow Black Relative Grey Light Grey Mid Grey Dark Grey KEY ISO Specification Tolerance E L*a*b* Tolerance E a*b*... Obligatory Out of tolerance - Red In tolerance - Green Informative Optional Out of tolerance - Orange In tolerance - Green N/A 11. N/A 11.8 N/A 8.3 N/A N/A Target ISO 5-3 Sample print E L*a*b* Sample print ISO Target Sample print ISO 5-3 ISO Sample print E a*b* Example Example Example Example -6 Mellow Colour -

25 9 Proof control report Proof control report By Paul Sherfield The test formes for the day were proofed on a GMG ColorProof v system and Epson 78 inkjet printers. Many thanks to BBC Magazines for the use of their new in-house prepress and proofing systems to carry out this task. The proofs were to the ISO coated, Fogra data 7, standard printing conditions, and initially validated to an average De of below 1.5 using GMG s Proof Control, and the Fogra Media Wedge After the print tests I was able, using the latest version of Bodoni s proofsign proof control system, v1.3.3, to validate the ISO coated proofs against the GRACoL G7 and Fogra 39 beta proofs used in the press tests. This is enabled by the software using the profiles to create proof control data for use in validation from the ICC profiles, change the expected values of the Fogra Media Wedge to match these profiles The following pages show the proofsign reports for the ISO coated proofs when measured using Fogra 7, Fogra 39 beta and GRACoL G7 beta data. The following can be observed: All pass the Fogra Media Wedge parameters. This implies that a G7 or Fogra 39 profile with print within the pass parameters on a press process controlled to Fogra 7, and therefore in any combination of the 3 profiles and printing/process control methods. This was also observed from the printed sheets on the test day. It can be seen from the Fogra 39 beta and the G7 beta proof control reports that the grey balance of the Fogra 7 proof is the area were these two profiles differ from this proof. The grey balance needed seems to be very similar for the G7 beta and the Fogra 39 beta, so reports of GRACoL using the Fogra 39 data as a base may be true? The cyan shows the most change within the primary colours. The specified paper white has changed a little from Fogra 7. 5

26 proofsign Certification Proof control report 9 Job name : Printed by : Proofer : Date / Time : BPIF tests ISO coated The Missing Horse Consultancy Ltd General Monday, July 31, 6 : 11: Pass Chart Standard : FOGRA MW.a - ISO Coated + Measured de Tolerance de Average 1.5. Pass - Maximum Pass Paper Pass - Cyan. 5. Pass -6 Magenta.9 5. Pass Yellow Pass Black Pass -8 Target Colours Measured Colours C M Y K Reference Lab Measured Lab deltaeab Report generated by proofsign by Bodoni Systems Ltd - 6

27 9 Proof control report proofsign Certification Job name : Printed by : Proofer : Date / Time : BPIF Fogra 39 beta The Missing Horse Consultancy Ltd General Monday, July 31, 6 : 11: Pass Chart Standard : FMW.a - Fogra39_temp1.icc + Measured de Tolerance de Average.6. Pass - Maximum Pass Paper Pass - Cyan Pass -6 Magenta Pass Yellow Pass Black.3 5. Pass -8 Target Colours Measured Colours C M Y K Reference Lab Measured Lab deltaeab Report generated by proofsign by Bodoni Systems Ltd -

28 proofsign Certification Proof control report 9 Job name : Printed by : Proofer : Date / Time : BPIF tests GRACol beta The Missing Horse Consultancy Ltd General Monday, July 31, 6 : 11: Pass Chart Standard : FMW.a - GRACoL_Beta 3 + Measured de Tolerance de Average 3.. Pass - Maximum Pass Paper Pass - Cyan Pass -6 Magenta Pass Yellow Pass Black Pass -8 Target Colours Measured Colours C M Y K Reference Lab Measured Lab deltaeab Report generated by proofsign by Bodoni Systems Ltd - 8

29 1 Acknowledgements Acknowledgements Many thanks are due to the following people and organisations who made this day the success it was by contributing time and facilities: Heidelberg UK for their showroom, Speedmaster 7, Mikki Winn and Steve Flower, and great refreshment Dan Wilson for his GRACoL G7 knowledge Eric Koldenhof for the PressView software Peter Arnel and the BPIF staff for organising the day Elie Khoury of Alwan Color Expertise for the use of Alwan ColorHub software Gretag Macbeth, X-Rite and Ripware for providing the spectrophotometers Eizo UK for use of a ColorEdge GC monitor for soft proofing Bodoni for use of their proofsign proof control software GMG UK for help with digital contract proofing, and BBC Magazines for providing the facilities for this proofing 9

30 BPIF Technical Committee ISO 167/- Printing Standards Test Day July th 6 Heidleberg UK The Missing Horse Consultancy Ltd