Discoloration on side of press sheet.

[lantz_xvx]

It's a Xerox C75 digital press burning the plates at 1200dpi. It works fine for everything else, including bigger solids than this one. *shrug* There's no other platemaking solution available to us at the moment, unfortunately. The digital press really does a good job with the plates, though.

 

[dabob]

It's not a solid, well in fact it is a solid but you keep saying that its not supposed to be . . . the transition from step to step can be very sharp in the imaging you might try looking at Gordos blog at

http://the-print-guide.blogspot.com

or this thread which addresses the issue here on print planet

https://printplanet.com/forum/prepr...low-discussion/4542-image-res-and-line-screen

I'm guessing here since you didn't say what screen ruling you are using but if you are using 100 lpi screening you will only be able to achieve 145 gray levels so you are losing 111 of the possible 256 gray levels.

It's been a long time since I was using a 1200 dpi device now we are using a 2540 plate setter but as I recall the less difference between starting % and ending % makes banding much more likely which I think might be your problem, without seeing the file thats the best guess I could make at this time . . .

 

[lantz_xvx]

Yeah, I mean that particular image is not a 100% "solid" but rather a big screen. One side of it looks fine, the other side of it doesn't. The line screen is 85lpi. But again, we've done smaller solids (actual solids) where the issue popped up and larger solids (11x17 posters with huge blocks of color) where there was no issue, all with the same platemaking workflow. A lot of folks who run poly plates are still using the HP5500 and these plates look a million times better than I ever got off that machine. So I'm hesitant to think it's a platemaking issue, although it's certainly in the realm of possibility. I'll take a look at these links tomorrow.

Thanks for the help and will send an update tomorrow.

- Lantz

 

[dabob]

running an 85 line screen will give you more grey values but . . . . solids is easy gradations are hard . . . specially in the 1 to 5 % areas they tend to plug . . .

 

[keith1]

If the gripper edge is where I think it is - I was confused by the posters description of this as well - then the job is being run 'portrait' and I'll throw my hat into the 'not enough ink/rollers to carry the solid' position on the matter. See attached for where I think grip is.
Don't know if this has been suggested already but you could try burning the plate with the image the other way around. That should give you an answer. If it is the size of the solid, try thinning the ink. View attachment gripper.pdf

 

[keith1]

PS/ being a 'Save The Date' I suspect this is a wedding announcement and anything to do with a wedding announcement is ALWAYS going to be a pain in the ass. I suggest you send the customer to a printer in town that you hate.

 

[Alois Senefelder]

Hello Lantz,

I see the problem now !!!!! you have a - Imaged Bar "Area" of high SID - many of the replys suggest you look at the

Plate Imaging, I agree

Regards, Alois


PS - The use of Polyester Plates should be - Banned!!

Think of the Planet, you can recycle Metal Plates NOT Polyester Plates made Using Toners

 

[AP90]

Hello Lantz,

PS - The use of Polyester Plates should be - Banned!!

Think of the Planet, you can recycle Metal Plates NOT Polyester Plates made Using Toners

Hey, not everyone can afford a CTP and metal plates. Especially when I'm sure the toner machine will serve multiple purposes for him vs. a CTP system.

 

[bill kahny]

Have you tried a new plate with the image flipped?

 

[dabob]

Hey, not everyone can afford a CTP and metal plates. Especially when I'm sure the toner machine will serve multiple purposes for him vs. a CTP system.

AP . . . there is this one thing about "multi purpose" machines, while they may do a lot of things OK they can't do everything with excellence . . .

Every machine has limits and you need to know what they are and not try to accomplish what they are not designed to do . . . .

 

[turbotom1052]

Im with dabob on the sharp line being a problem imaging the gradation. If you've tried everything mentioned with still no luck Id suggest that you replace any transparent white in the inks formula with opaque white. If there is no white in the formula you might try adding some anyways. Ive seen opaque white hide a multitude of sins.

 

[Tomtech]

Try burning a new plate upside down and further down so you can mount it on the press upside down. If you can put the image further down the paper, good. If the problem stays in the same place it may not be a press issue. If it is a press issue and you run the image upside down the problem area should stay in the same spot on the press. If it stays in the same same place on the image, it is not the press. Good luck.

 

[lantz_xvx]

Hey folks, I actually had no idea about these replies. I'll let other people argue about poly plates versus metal CTP. I've got nothing to say about it except, everyone has to do what's right for them and their business. Incidentally, we sent this job out a partner shop with a larger offset press and while the came out a lot better, it still had a line in the print. They were using metal plates. So... like I said before, platemaking wasn't the issue. So we ended up doing the job digital and then duplexing the printed sheet with a blank sheet to get the thickness they wanted. Then they realized that the date they wanted at the venue got taken (why didn't they get that solid before they placed the order?) so then we printed them again. It was the job that never ended. We probably spent more than we made on it, but it was for a client that sends us a lot of letterpress work where the margin is better. So, no one get married anymore, ok?

Thanks all,
- Lantz