Erasing Thermal Plates

[Captweez]

I wondered if anyone knows any good way to remove image, for instance, spots, characters that don't belong, etc from thermal plates. (touch-ups)

The pressmen have tried the traditional removal solution they used on the old fashioned traditional metal plates, but it seems to create a blob or smudges.

Any suggestions?

 

[Al Ferrari]

The ones made for analog plates cause the problem you describe. There are similar deletion pens made specifically for thermal pates. Check with your plate supplier or your fount chemistry supplier.

If you are not already doing so, you should also check into fountain chemistry specifically formulated for thermal plates.

Al

 

[Captweez]

Thanks Al,
I've only been with this company in Prepress for about two weeks. At my old company, we used the conventional metal and polyester plates for some jobs.

The thermal CTP system is new to this company as of January. I would have hoped that when they got the new system, someone explained to them about the fountain chemistry, but who knows.

It's not 100% clear to me whether they are using the old deletion pens, or whether the new "thermal" pens just aren't as effective as the old ones were on metal. I've heard mixed words suggesting both, so I'm not sure. They don't like me nosing around the pressroom too much... Since I've only been their two weeks I have to be careful about stepping on anyones toes.

 

[Cory Smith]

we never found deletion pens that worked well on our Fuji Thermal plates..They would eventually work, just took lots of rubbing.

 

[Al Ferrari]

Have you tried these?

Nikken Deletion and Addition Pens

I only just learned about them. The shop where I get my Fuji Thermal plates is using them.

Al

 

[Al Ferrari]

I too recently started using Fuji Thermal plates because that's what is being used at the shop that's making them for me. But they also only recently converted from analog plates.

Fuji put in the platesetter and gumming washout unit, but gave them absolutely no advice on the press fountain chemistry. So we were both getting toning and picture framing, until we found out about the need for different chemistry than for analog plates. We are now using Anchor MXEH 1 Step #9212-1, and the problems went away.

Good luck,

Al

 

[Captweez]

I investigated a little further and got this description.

They are using new deletion pens that were sold to them by the same people they get the plates...

The pressman describes the problem as such. It's not a matter of the fact they don't work at all they seem to work "too well". He basically said not only does it remove the top layer of image (the emulsion, I guess?), It takes away something underneath it that should stay. So when they try to delete it, the plate picks up ink in that spot. If that makes any sense.

Out of three pressman, the only one who's ever been able to get it to work successfully said he was impractically careful to just use a tiny amount of the deletion fluid.

I only started to care when I notice they were occasionally coming back to prepress for new plates for things that should be easily solved with the delation pen. (Or at least would have been on conventional plates)

Maybe thermal just doesn't erase well? I'll find out about the plate brand and the brand of pens.

 

[bluekivi]

We are able to delete image off of plates using an old deletion pen dipped into the developer. It takes a little while but eventually the image fades away. Using Kodak Thermal Gold plates.

 

[Al Ferrari]

It turns out those Nikken pens aren't worth a dam either! They don't work for me or the shop where I get my Fuji Thermal plates.

Al

 

[Cory Smith]

The Nikken pens were the ones supplied to us by Enovation as the pen to use on our fuji plates. .Same result as you Al. Gave up on deletion pens in favor of no longer making mistakes let you know how that works out.

 

[RGPW17100]

As mentioned you really need to work the pen on a wet plate. A dry plate they work fine. We use Azura plates by Agfa and the trick is to use Azura plate cleaner after you use the pen. Not sure if it will work for fuji though. As your press operator mentioned after using the pens it looks like you can see the shiney aluminum like the back sides of the plates. The plate cleaner helps this however when we used a conventional plate cleaner scratch remover it also removed the image and the plate was not serviceable. Ask your fuji supplier for a plate cleaner for those plates. If they dont make one they sell a product similar to agfa FPC that will work with the pens and you can also use it as short term storage gum.

 

[rich apollo]

The Nikken pens are excellent. They work great on thermal plates. I was using them on Fuji LH-Pj plates. The trick is to let the chemical sit for a minute or two. Don't keep rubbing - the process is not instantaneous on these plates. Remember to rinse and gum the area after, cause those puppies are aggressive as hell.

I also found out by accident that the 'wrong' scratch remover makes a dandy image remover. Doesn't tear up the anodized surface like image deletion pens.

 

[Al Ferrari]

Rich,

Good to know about the time delay for the Nikken pens. The normal tendency is to "quick rinse without waiting before the smudge adheres." We'll try it and see.

So which brand makes the "wrong scratch remover" please? Struggling pressmen want to know!

Al

 

[Ritter]

The Heidelberg (Agfa) pens and the Kodak pens I've used have worked quite well with the thermal plates provided by the vendor. Strongly recommend using same vendors pen with plate.

 

[Al Ferrari]

"As mentioned you really need to work the pen on a wet plate. A dry plate they work fine."

So which is it: do it on a dry plate, or on a wet plate?

Al

 

[rich apollo]

Rich,

Good to know about the time delay for the Nikken pens. The normal tendency is to "quick rinse without waiting before the smudge adheres." We'll try it and see.

So which brand makes the "wrong scratch remover" please? Struggling pressmen want to know!

Al

Yeah, pressmen would come in to me all the time with the end of their Nikken pens all mashed out - looking like a flower in full bloom. They'd ruin a pen in one use - while I could keep one for months. Pressmen are so...twitchy; impatient. They're like having a pack of very large chihuahuas running around the plant.

Honestly, Al, I don't remember. I think it was Fuji or Prisco, but it could've been some old Kodak stuff we had laying around. I don't know that it has to be a specific scratch remover, just one that is contra-indicated for your plates. Each chemical company has several scratch removers that are recommended for different plates. We just happened to try one that softened the emulsion on that plate.