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General Category => CTP - CTF => Topic started by: Holsinger60 on July 08, 2019, 08:42:34 AM

Title: Fingerprints on Plates
Post by: Holsinger60 on July 08, 2019, 08:42:34 AM
So, we use Fuji Superia LH-PJ plates here. About every 3 months or so, the production floor comes up complaining about their plates inking up fingerprints all over the place. I've tried to recreate the problem by having everyone on my shift slam their hands all over the plates pre and post imaging/processing. No joy.

I was just curious if others have had similar issues and if they found what the cause was. Really don't want my plate department to have to wear gloves all the time. And they don't either. TIA
Title: Re: Fingerprints on Plates
Post by: Possum on July 08, 2019, 12:12:18 PM
We use Fuji plates of a different ilk, but I've never had that happen here. I handle them as little as possible, and with the slip sheet on. Of course, the pressmen are another matter.

The only things I can think of is that somebody handling the unfinished plates had something on their hands, or their body chemistry is such that acids on their skin actually affect the plate coating. See if more frequent hand washing makes a difference, although I'm sure that suggestion will be taken up enthusiastically.  :sarcasm:
Title: Re: Fingerprints on Plates
Post by: David on July 08, 2019, 12:28:36 PM
Are these hand loaded into the platesetter or are you using an auto-loader?

If these are hand loaded, someone is touching them all over when they load them in, nothing to do but stop touching the plates, only handle them by the edges. We had some issues (another brand of plates) that we had a similar issue, turned out 1 platemaker had extremely oily hands, he had to end up wearing gloves.

If it is an auto-loader, then they must be coming from the factory like that.

Have you sent out a plate that has not been touched by humans to see if they finger print as well?
Title: Re: Fingerprints on Plates
Post by: JohnO on July 08, 2019, 12:36:48 PM
Everyone has to wear gloves when handling plates at our shop. It's a safety thing as well as plate edges are quite sharp and many of the plates sizes are quite large.
Title: Re: Fingerprints on Plates
Post by: scottrsimons on July 08, 2019, 02:34:39 PM
Same plates here, but no problems. I have seen fingerprints on the back side of plates after it's been processed, but no problems, as we only touch them around the edges, and we have an auto-loader.
Title: Re: Fingerprints on Plates
Post by: Holsinger60 on July 09, 2019, 11:54:58 AM
No auto-loader here. Hand loaded into platesetter. I've never been able to narrow it down to a certain individual either. Seems to be mostly on plates where after they've processed we have to cut down on a manual cutter. A lot of folks will steady it by pushing down on it. Maybe I should require gloves when doing that process and see if it clears up any.

Thank you all for your suggestions and advice. I certainly appreciate it.
Title: Re: Fingerprints on Plates
Post by: Farabomb on July 09, 2019, 01:33:38 PM
Ran those plates for years. Depending on the mood of the pressman I would get some complaints of fingerprints. Sine I was the only one doing everything, I know where I handle the plates and anytime they would show up, it was nowhere near the edges where I grab them.

I've seen some prints but they were in the platebend and gripper so it wasn't a major issue. Since it's handfed I'd have the loaders only use the edges and see how that works.
Title: Re: Fingerprints on Plates
Post by: Tracy on July 09, 2019, 01:46:05 PM
Line everyone up for fingerprinting!!  :laugh:

I use fuji and I always grab a plate by the edges, when it comes out of the imagesetter it is super sensitive.
I always slip sheet too.
Title: Re: Fingerprints on Plates
Post by: wonderings on July 09, 2019, 01:53:41 PM
Seems very peculiar to have finger prints all over the plate as they really do not need to be handled all that much and certainly not in the centre of the plate or where the image will be. Like others I take plates by the sides and once imaged I put one of the slip sheets that comes with the plates between it.
Title: Re: Fingerprints on Plates
Post by: Joe on July 09, 2019, 01:57:13 PM
When I make plates I usually leave blood on them.

:facepalm:
Title: Re: Fingerprints on Plates
Post by: Possum on July 09, 2019, 03:06:56 PM
During your long prepress career, you've probably left blood in a lot of places.  :lmao:
Title: Re: Fingerprints on Plates
Post by: Joe on July 09, 2019, 03:09:26 PM
Not nearly enough!

:facepalm:
Title: Re: Fingerprints on Plates
Post by: AaronH on July 09, 2019, 05:51:07 PM
Unless something got on the plate and an operator is trying to brush it off, I can't see a reason to touch the plate center, or anywhere outside of the first couple inches. I try to minimize plate touching as well and usually end up getting cut, though usually not bleeding. I'm short though and the big 40" plates are hard to manage.
Title: Re: Fingerprints on Plates
Post by: Joe on July 09, 2019, 06:17:14 PM
Our biggest plate is 57" x 49.5" and they are a bitch to handle.
Title: Re: Fingerprints on Plates
Post by: StudioMonkey on July 10, 2019, 03:11:07 AM
Quote from: Holsinger60 on July 09, 2019, 11:54:58 AM
No auto-loader here. Hand loaded into platesetter. I've never been able to narrow it down to a certain individual either. Seems to be mostly on plates where after they've processed we have to cut down on a manual cutter. A lot of folks will steady it by pushing down on it. Maybe I should require gloves when doing that process and see if it clears up any.

Thank you all for your suggestions and advice. I certainly appreciate it.
You've got fingerprints - it should be easy to identify whose they are with a loupe.
Title: Re: Fingerprints on Plates
Post by: pspdfppdfxhd on July 10, 2019, 09:32:23 AM
Quote from: StudioMonkey on July 10, 2019, 03:11:07 AM
Quote from: Holsinger60 on July 09, 2019, 11:54:58 AM
No auto-loader here. Hand loaded into platesetter. I've never been able to narrow it down to a certain individual either. Seems to be mostly on plates where after they've processed we have to cut down on a manual cutter. A lot of folks will steady it by pushing down on it. Maybe I should require gloves when doing that process and see if it clears up any.

Thank you all for your suggestions and advice. I certainly appreciate it.
You've got fingerprints - it should be easy to identify whose they are with a loupe.

About 20 years ago, I had a brief stint at a billboard printing company and they used 77 inch plates. Took awhile to learn how to manouver those.
Title: Re: Fingerprints on Plates
Post by: Farabomb on July 10, 2019, 10:03:49 AM
That's a big ass plate. I assume very carefully was how you move those.
Title: Re: Fingerprints on Plates
Post by: Savage on July 11, 2019, 08:23:36 AM
Had the same problem with the same plates. We eventually figured out that the fingerprints where from the press operators when loading the plates to the press.
We solved it by changing the gum. We used the finishing gum on a 1:2 dilution. We changed to 1:1 and the problem went away.
Hope it helps.

Edit: I just remebered another thing. At the time we used Fuji's FN-6E gum. At the time of the problem, our Fuji rep advised us to change to another gum (besides changing the dilution). So, after we finished all the FN-6E gum we had in stock (without further issues), we changed to Fuji's FG-8E gum. We kept the 1:1 dilution, and haven't had any issue since.
Title: Re: Fingerprints on Plates
Post by: Possum on July 11, 2019, 08:27:09 AM
So the guys complaining were the guys causing the problem. Figures.
Title: Re: Fingerprints on Plates
Post by: Savage on July 11, 2019, 09:01:06 AM
Quote from: Possum on July 11, 2019, 08:27:09 AM
So the guys complaining were the guys causing the problem. Figures.
Yes, but trying to convince them that they're the ones causing it is an almost inpossible task! :deadhorse:
I should win a Nobel Prize just for trying! :lmao:
Title: Re: Fingerprints on Plates
Post by: Tracy on July 11, 2019, 01:29:30 PM
 :laugh: I was wondering if it was the Press Ops!!
Title: Re: Fingerprints on Plates
Post by: scottrsimons on July 12, 2019, 05:13:46 AM
It's never the Press Ops!! At least in out shop. It's always Prepress!!
Title: Re: Fingerprints on Plates
Post by: AaronH on July 12, 2019, 10:29:16 AM
Quote from: scottrsimons on July 12, 2019, 05:13:46 AM
It's never the Press Ops!! At least in out shop. It's always Prepress!!

Especially if they punch the plate wrong and it's now off center. Definitely prepress' fault for not imaging the place centered in the machine that measures the plate to know where to start and make sure its centered...