Press Fingerprinting

[irreality]

Hi, First off I guess I should introduce myself, since I figure I will be asking alot of questions in the near future. So hello everyone ! hope you guys can help a newb

Anyways,

Im not necessarily a complete newbie to the entire print scene - however this is the first time Ive ever had to start up a complete prepress environment from scratch, and I know this is an extensive process and I will try not to bore you all with the nitty gritties....

Anyways, the first thing Im trying to wrap my head around is press fingerprinting and calibration. If anyone is willing could you outline the process for me start to finish, by explaining all the technical jargon... or if you know of a good website or book to look at I would greatly appreciate it.

I know im not the first person to do this so Im sure someone will be able to help, and Im really not alone on my end - I have a great team behind me who has done this a few times, I just want to get as much knowledge as i can before I need to call in the heavies.

Thanks again.

 

[gordo]

You might want to rummage around here:
my print blog here: Quality In Print
as well as these two posts:
Quality In Print: The Golden Reference - part 1 of 2
Quality In Print: The Golden Reference - part 2 of 2

best, gordon p

 

[rich apollo]

I would encourage you to download and read the G7 How-To. It's a pretty complete document.

IDEAlliance

Perhaps the toughest challenge of press calibration/fingerprinting/profiling is determining your target.

 

[KRizzo]

There are two types or parts to fingerprinting to determine "Are You Printing Well?"
1. Fingerprinting the current state of the machine
2. Fingerprinting the current state of the print process

Ken Rizzo
Director of Technical and Lean Services
Center for Technology and Research (formally GATF)
Printing Industries of America

GATF developed and establish the first and officially recognized press testing and analysis targets and methodology over four decades ago.
The Center for Technology and Research's Print Analysis Laboratory regularly conducts press test sheet analysis.

 

[Halit Kolsuz]

Hi every body,

Finger print session needs very good ink and machine standardization experience. Especially, if you are using Offset Printing System You can take very good feed back as color management. In Gravure and Flexo printing systems, Lower viscosity ink is used because of this reason; to take %100 result from color management systems is very difficult. %85 is very good result for those systems and you can decrease your waste ink and waste printing substrate. And you can begin to print in a short time in your printing processes; you can save time by means of this system.

There a few rules that we have to above for the finger print session of the color management system. Those rules will help you to create useful finger print.

1. Stable input/raw material: If you want to take good result, you have to use all time same CMYK inks and substrates. For each different substrates that you will use in your finger print session, you have to make different finger print session because all substrate have different visual and density. And your result will be affected from these differences.

Exp: White OPP and OPP + White ink (need a different finger print session.)

About Inks: CMYK color that you used on your printing system should be same for each production. This is the most important rule for the finger print session because color is the result for the printed material. If you want to create alternative CMYK color because of the procuring problems, I propose that you work an ink expert. You can find very good CMYK colors that are same with you used. But I want to draw your attention to Half tones because CMKY color are working as half tone about %80 because of this reason, you should check all colors with drawdown and a color must be same as %10 - %20 - %30 … with the reference color.

2. Machine Standardization: You have to use your standard on finger printing session. You don’t constraint your machine setting to take perfect result, only you should observe to print good finger print patch. And you have to use standard densities and measure with spectrophotometer to make sure density. If you have not density standard, you can use European Standards.

Proposal: Please be careful to choose density standard of the CMYK colors, because high density make your printing result very shine but at and of the printing you will have very expensive product. Choose what you need.

3. And make profile your Print Out according to your finger print result and check again on the printing machine with same densities.



If I can be any further assistance, please let me know.
Good Luck

 

[Print Guru]

Hi,
Practically speaking you need a standardized print target that has hundreds of color patches, CMYK screens and more. The target is a file that u output to a plate and print on your machine with all CMYK solid densities carefully controlled and match to a specific standard.
Now, all the hundreds patches on the print will be read by a special spectrophotometer. The data will be compared by software to the data of the target file that was used to expose the plate.
The result of the software is a file called "ICC profile". This file is submited to the CTP to correct the exposure - for your machine – only for paper you have printed.
Yes. You need to run the same for every paper u print on the machine.
Well, I made ICC's for coated paper, uncoated paper and one recycled paper.
Please note that my explanation is very general.
Since this process is very professional with lots of know how I suggest u call a pro to guide u around.
I suggest u make 1 run on coated, make the first ICC, run a second test on coated. Check visually, if u r satisfied then runs the other papers.
-PG

 

[gordo]

Personally I think that fingerprinting a press is separate from creating ICC profiles. There's no point in building profiles if the press condition is unstable.
When you fingerprint a press I believe you are capturing information about its current mechanical print condition. You're looking at things like ink water balance issues, voids in solids, nested dot gains, SIDs across and around the cylinders, etc.
Once you've determined that it is functioning within normal parameters you would calibrate it - i.e. bring it to a specified condition (e.g. SWOP, GRACoL, etc.). Perhaps create tone rep curves, change ink hues, etc.
Once its calibrated you would characterize that condition to confirm that it has been properly calibrated and, if required, create any needed ICC profiles.

best gordon p

my print blog here: Quality In Print current topic: dot gain/TVI

 

[PDeuth]

Let me chime in with this: there is variation in every process, and in a system such as a printing press, there are many processes all working at the same time, adding to the total throughput variation of the press. If your data from press profiling is to have meaning, it needs to represent some kind of standard press output, which is a reflection of some kind of operating conditon. The independent variables on press will determine the output: I can think of a half-dozen ways to change a 50% dot, all of which have other consequences on the output, for instance.
There are some things you need to know and do before profiling a press.
1. Have a production strategy: does the profile represent average, or optimal conditions. What will the profile be used for? How will it be used?
2. Set up your press to run according to your strategy, and make records of each and every setting. As soon as you change one of those (input/independent variable) settings, your profile becomes meaningless.
3. Determine the variability of your press by pulling ramdom sheets over a press run and measuring them. This will provide guidence to how many sheets you need to pull and measure when it comes time to profile.
4. Determine the accuracy and precision level of your profile. The number of sheets you need to measure depends upon this determination.
5. During the trial you ran to determine press variability, you have taken data which will allow you to indicate whether your press is running well, if the press condition is stable. Before you start to pull sheets to measure for your profile, make sure your press is stable.
6. Pull your sheets at random intervals. Allow them to dry. Reject all that have slur and doubling, unless you consider slur and doubling a normal, acceptable output parameter/variable.
7. Calibrate your instrument. Better yet, use several different instruments. These have variability, as well, and a seperate statistical trial might be done to establish that amount.
8. Measure and average your data. Make your profile according to the instructions in your software.
9. Test your profile using test images in Photoshop, ColorThink, and/or your profiling package.
10. Finally, test your profile and press set-up to see if the results match those you would have expected. If they don't, and if you're not getting good results after several jobs/tests, start over again.

Sounds like a lot of trouble, and it is. I've never been permitted to do it right, and I've never heard of anybody else doing it right. Perhaps there's someone in PrintPlanet who has had this happy experience. It's important to remember that your future output depends on your press profile. If you screw it up and just "wing it, hoping for the best," your future output will reflect all the inaccuracies in your technique. That's a big potential OOPS.

 

[Simon Landau]

Hi guy's - I am a colour consultant in the UK and the first to achieve FOGRA's Process Standard Offset certification to ISO12647-2 for a printer here.
I would like to throw in my two peneth on this question.
Press Fingerprinting and Press Standardisation mean two different things over here. The first relates commonly to an ICC profile created from a series of press sheet measurements taken from an "optimum" run. This ICC profile may then be used for seperation (target data will need to be smoothed prior to building) or as a proofing profile for an ICC based proofing system.
I think the question set actualy relates to the later Press Standardisation. The following is a brief explanation of process used to achieve this goal. Of course the first step is to decide which print standard you wish to run to i.e G7, SWOP, FOGRA39L, 3DAP etc, etc (some of which are very close an aim at ISO12647-2).
When you have decided this you will idealy use a software/workflow tool that will allow you to standardise to the defined tolerances for whichever standard chosen. In the case of FOGRA we have primary targets with a tolerance of delta E <5 and dot gain targets with a 3% tolerance in quater and three quarter tones and a 4% tolerance in mids.
Obviously the plate and press production process needs to be optimum before conducting the standardisation and your inks should conform to the standard you wish to achieve in our case ISO2846 but even then we have found that some inks are better than others in terms of matching to ISO12647-2 i.e Magenta, Yellow, and Black may all achieve low delta E's of around 1.5 but the Cyan may only be able to achieve 3.9 for instance. This will not give you much tolerance for density on cyan and may result in problems trying to maintain accuracy. All apects of the print process need to be noted and the press needs to be mechanicaly sound. If you start this process with issues it will be a waste of time when those issues are fixed. No new blankets or old ones etc, etc, etc.
Step 1, Run the wet density to dry Lab test to establish your ideal wet (on press control or make ready) denities. The different packages have their own way of doing this but in my experience there is no substitute for allowing a coated sheet using conventional inks to dry for at least 6 hours or 24 for an uncoated.
Step 2, Once you have established the lowest delta E to density correlation then optimise these based on good Blue, Green and Red overprint in that order. We see differences in those colours in that order.
Step 3, Take your first dot gain readings from linear plate and allow the software to generate smoothed compensation values for your first plate setter curves.
Step 4, The software I use allows for this process to be repeated thus iterating or improving the dot gain compensation until accuratley matching your targets. If done right then the CMY curves match and produce great grey balance and will match accurate proofs run to your chosen standard.
Step, 5 Choose a package that then allows quick analysis of the continued state of your press by the simple reading of control wedge which will then allow you to easily update you curves if nessecary due to the change in press output due to enviromental difference. This check may also point to mechanical problems that may occur on press such a roller pressure problems or blanket life etc.

It is not necessary to repeat this process for all you stocks. We mainly recommend the grouping of coated, uncoated and speciality stocks that have similar spread characteristics and use your most common as the reference. For all other stocks you must take a view as to the time invested versus the value attatched to the use of the stock in question. It goes without saying that if you want consistancy in your production then this process needs to be completed for each press and not "one genereic in between curve that suits all" as this just does not work.

I could write a whole lot more on this but must get back to work - hope it helps and good luck.

All the best,
Simon.

 

[sherry_xie]

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could not open

Hi gordon p,

these websites are not avaible to open.

Regards,

Sherry

Personally I think that fingerprinting a press is separate from creating ICC profiles. There's no point in building profiles if the press condition is unstable.
When you fingerprint a press I believe you are capturing information about its current mechanical print condition. You're looking at things like ink water balance issues, voids in solids, nested dot gains, SIDs across and around the cylinders, etc.
Once you've determined that it is functioning within normal parameters you would calibrate it - i.e. bring it to a specified condition (e.g. SWOP, GRACoL, etc.). Perhaps create tone rep curves, change ink hues, etc.
Once its calibrated you would characterize that condition to confirm that it has been properly calibrated and, if required, create any needed ICC profiles.

best gordon p

my print blog here: Quality In Print current topic: dot gain/TVI

 

[gordo]

Hi gordon p,
these websites are not avaible to open.
Regards,
Sherry

Very odd. Try these (the http:// goes in front of "qualityinprint":
my print blog here: qualityinprint.blogspot.com/
as well as these two posts:
The Golden Reference - part 1 of 2: qualityinprint.blogspot.com/2009/02/golden-reference-part-one.html
The Golden Reference - part 2 of 2: qualityinprint.blogspot.com/2009/02/golden-reference-part-2.html

best, gordon p

 

[KRizzo]

Total Production Maintenance

Total Production Maintenance

Printing Industries of America Press
Book
"Total Production Maintenance a guide for the printing industry" 3rd edition by Ken Rizzo is the only industry publication that tells, shows, and describes How To do all this; control, optimize and print well.

Ken Rizzo
Director for Technical and Lean Services
Center for Technology and Research
Printing Industires of America