When did they just randomly decide to change their print sequence???
If you are running to a standard (I'm only familiar with ISO) they cannot be doing that.
"Strange things are done in the land of the midnight sun by the men that toil for gold."
BeauchampT/contrakid
Black (K) can be printed First or Last, I suggest you read "Gordo's " Blog - - -
"Quality in Print"
Regards, Alois
OK I know you can print black last we have done it on and off for years but only when last resort. I know some types of printing have to print last. Newsprint etc.
But if you trying to match ISOcoatedV2 / Forgra39 standard your going to get much closer with Black under CMY not on top and i am talking about Litho offset sheet fed printing.
So do you think 100% Yellow onto of 100% Black looks the same as 100% Black on top of 100% Yellow?
I don't know who you're directing your comments towards. If it's me then I agree, for sheetfed the sequence is KCMY. For newspapers it can be KCMY or YCMK with YCMK being preferred.
I don't think 100% Yellow on top of 100% Black looks the same as 100% Black on top of 100% Yellow.
It would be interesting to know the OP's press operator's thinking behind switching to K last down. What problem did he think he would solve with that strategy? How did he think changing the ink sequence would solve it?
best, gordon
Think they struggle with large black solids marking when on first unit. I don't know why this would be, maybe you can advise me. But although i get on great with all of our Press minders I don't have great confidence in them sometimes.
Unfortunately in the real world these days Press minders are put under great pressure to turn out as much work as fast as possible and still achieve a high level of quality for low production costs.
Hence sometimes corners seem to be cut.
This is not helped by going from a very long run low quality job in the morning to a very high quality short run job in the afternoon syndrome!
Also we have had some new spray powder cause text to breakup after very short amount of run after blanket being cleaned. So possibly they have been putting black on 5th and using first unit for dusting until we get better spray powder back in!
Would this explain things?
Printing is complicated - with a great many variables. That is why standards and process control are so important as well as documentation and an organized method to correct deviation (problems) when results are not what is expected.
There are many reasons why this would occur. Has this always been a problem? Did it just start with a certain job? What has changed in your process? etc. (standards, process control, documentation, etc.)
This has been my experience since I first started working in printshops in the mid 1960s - and I know from the literature that it was also true from the beginning. To wit: "Hand writing all these Bibles is too slow, expensive (the cost of wine to keep the monks happy is ridiculous), and the quality is all over the place - we can't get two Bibles to look the same! Hey Gutenberg, got any ideas for a faster, cheaper, and better way to churn out these Bibles?"
No, this is where standards, process control, documentation, etc. come into play. Cutting corners is the lazy way and doesn't work.
No such thing as low or high "quality" jobs. The manufacturing process is the same. The press itself treats all jobs the same - so should the staff. What may change from job to job is the tolerance for variation from the proof. Sounds like an attitude and management problem - not a technical problem.
Sounds like a rationalization for a lack of standards, process control, documentation, etc. "We didn't have the time to make a sacrifice to the litho-gods before our shift started. That's why we moved black to the last unit."
Yes, gordo
hi everyone,
what is the CMYK standard value of print contrast?
I don't believe there is one since print contrast is not a target but an indicator of ink/water performance.
Published typical reference values are: K 40+ C 35+ M 35+ Y 30+ The plus + means that if you can achieve a higher value that's better.
Print Contrast in film days was an indication of print quality because the values correlate well to the subjective evaluations of print quality, such as “flat” (low print contrast values) versus “jumps off the page” (high print contrast values). Print contrast is often used as a guide for maintaining proper ink/water balance. But in a CtP world you can apply plate curves to have virtually whatever print contrast you want.
GATF described print contrast as a value of 75% screen tint (film/CTP or otherwise) and solid. The late Ken Rizzo (GATF) measured the higher density of magenta in G7 sheets and noted that the print contrast value dropped when the density reached 1.50 (The 1.44 density created the best print contrast number). A lower number represents a poor print condition. Pressroom research is a thing of the past. .
Pressroom research has been a thing of the past for decades. Even when it was being done - it was often done so poorly as to be next to useless - even when done by GATF.
Ink is a major input variable but it is not controlled properly now. It should be.
I dare any researcher out there to do a proper test of the process and report the results. But they will probably not take up that dare because they want to think that they are already doing science, which they aren't. They are only doing industrial trial and error experimentation.
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