Prepress vs Press Finger Pointing (Plate Remakes)

prepressdork

Well-known member
Hi everyone,

It's an ages old argument. When something goes wrong on press, is it a press or prepress issue?

When it comes to plate remakes for things like spots/scratches/holes in a CTP world, it's sometimes not easy to know exactly where the problem occurred. Last week, I had to remake a plate because of holes. When I looked at the press sheet, to me, it looked like chemical spatter ate the emulsion. Of course, the pressroom says, the plate came out that way to which I ask, "Why didn't you bring the plate to me before putting it on press?" Their response, "This is how it looked when I got it on press." So we...really...don't know for sure where the problem occurred. I will say however that it very well could have been a bad plate. Sooooooo.......

I was thinking about trying to come up with some sort of camera system that takes a picture of each plate after it is imaged/processed. Has anyone ever done something like this? I realize this might be overkill or even silly but when the pressroom throws me in front of the bus without proof, I feel compelled to act.

Thanks,
pd
 

gordo

Well-known member
At the shop where I worked every plate was checked for defects before being hucked over the wall into the pressroom. The person who inspected the plate, initialled the plate. That way if there was a problem like you describe occurring in the pressroom there was some way to trace where the issue arose. We also photographed plate and press defects and documented their cause so that we had a reference for future issues. Press and prepress issues were also discussed in a rountable at our daily or monthly meets.
Mistakes happen. But they should only be new ones.
 

Cornishpastythighs

Well-known member
my word you must have hundreds of plates remakes to justify a camera to photo every single plate that leaves the department, dont forget some issues dont become visible till the plates are inked up.
Better to spend your money on good process controls in the plateroom, Have the CTP unit checked out, have the processor checked and then establish controls along with training. Have your press people learn how to make plates. Document every chemistry change and how many plates were made in between. Have you plate supplier in to discuss plate issues and give training if required. Cheers my 2 cents worth.
 

gordo

Well-known member
Another thing to try in this kind of situation is to try to recreate the problem. I.e. What chemical splatter in prepress could affect the plate coating and what chemical splatter in the pressroom could do it? Burn a plate and hit one side with the chemical in prepress and the other side the pressroom chemical. Then mount on press and run and compare the results to each other and to the original press failure.
 

prepressdork

Well-known member
Gordo - we do our best to check plates before they leave prepress but as Cornish said, sometimes some issues are not visible until the plate is inked up.

Cornish - that's just it, we don't have a lot of plate remakes. So far this year, 71 plates have been remade for non-content issues (not including customer alterations) and we average about 2000 plates per month. You may be thinking that 71 plates is a drop in the bucket but that's not how bossman sees it. We do have good process control in prepress (I believe we do at least). The platesetter and processor have been checked out by service and myself (nothing was found) and because these remakes are not repeatable (no discernible pattern), we haven't yet felt the need to contact our plate supplier yet. We probably could improve our documentation process though.
 

wonderings

Well-known member
The only time we really have to remake plates is if there is something wrong with the file. Been years since we had any damaged plates. Had a few crooked plates and that was user error on our old Presstek. With our screen 4100 it has been perfect, at least in terms of plates imaged with no damage.
 

Cornishpastythighs

Well-known member
doesn't sound like you have a chronic problem so photographing every plate is mass overkill. Usually the biggest culprit is blanket/roller wash and also rubber rejuvinator. This gets on the plate usually from a blanket washing and was not dried up properly so when the press starts up the wash splashes out of the blanket gaps .
 

Lukew

Well-known member
Interesting to hear someone else outputs your plates. I have to output my own plates, clean the machine etc. Worse still being polyester they don’t simply output on top of each other and will turn into a jumbled rolled up mess so you need to routinely check them. I don’t mind out putting plates but when you have 16 - 20 make readies to do in a single shift can equal a lot of plates. Then there’s the lost time if there is something wrong with a file. Not to mention finding stock off shelves for the jobs.
I hear some people are also lucky enough to have the paper already allocated for the job & ready to go so they simply load up.
 

CKL

Well-known member
Gordo is correct about the chemistry test plate.
Tell the Pressroom you want every "bad" plate back with their initials on it. Pressmen, 2nd Pressmen, floor guy, helper...whomever may have serviced the plate on press and/or filled the chemical bottles on the press. You might spot a trend that could be quickly addressed. Is the emulsion completely gone? faint? or not taking ink. Do all the "Bad" plates look the same?
 

kansasquaker

Well-known member
You may be thinking that 71 plates is a drop in the bucket but that's not how bossman sees it.

Assuming you're running 40" plates, that's almost $500 wasted throughout the course of this year. How much time has the company spent tracking and discussing the defects? I'll bet that adds up to way more than $500.
 

Magnus59

Well-known member
We've had batches of plates that had intermittent emulsion defects from the factory, they couldn't be seen on an unexposed plate, but presented as holes in the image. This resulting is a finger pointing exercise between Prepress, Pressroom and plate manufacturer.
We've also had the Pressroom point the finger at Prepress for diagonal scratches inthe plates, how on earth you get diagonal scratches onj plates travelling through a plate line I have no idea. At that time the press operators wanted the plates supplied to them with no interleaves because they didn't want to spend the extra time taking them out. After the scratching issue, we went back to interleaving every plate before it left Prepress, the scratches miraculously disappeared. The press operators would never accept that they were handling marks from when they picked up the plates to put them in the bender.
 

Raymond Ramirez

Well-known member
At 71 bad plates for every 2000 printing plates. That's right about 4 to 5% spoilage. I don't know about you but if somebody said that they were going to take 45% out of my pay I would kind of be pissed. I think I had read earlier about process controls. As a technician I have seen on plates depending on which device you have causing a degradation of the plate within the pre-press department. Such as a leaky air valve on a trendsetter or a blown hydraulic shock that is dropping oil on the plate or onto a roller that rubber stamps the plate. Even though there is miniscule handling of printing plates nowadays it still happens.
 

DuaneBryant

Well-known member
1) Mr. Ramirez: he said 2,000 plates per month, which would be at least 20,000 plates so far this year with only 71 remakes. An incredibly low number.

2) I had to do meticulous inspection, documentation, and record keeping for months one time to get a major plate manufacturer to finally admit that they had a process procedure and contamination problem that was spitting out millions of square feet of randomly and sometimes very tiny areas of defective plate materials on an ongoing basis. Took months to clear that up. Don’t assume the incoming raw materials are without a problem.
 

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