Spot Color Mess!

[gordo]

I got the Chinese POS too, and sometimes it works, but usually after several restarts.
So a short while ago I did a little of what Alith7 did and used my phone's camera with my Beta ColorViewerIII.
This pic is using the 100x adapter. Un-retouched.

Looks like a dot selfie!

 

[Ulrich]

hi, Alith7

Do i get this information correct?:

Customer wanted to fill in the "white" areas of the screened PMS with yellow.

Means that, that you and your customers aiming to fill the paperwhite avoided(?)/not filled "negative dots" in a grafic objekt like a headline font or just a square or circle or whatever coloured with a 50%-value PMS 1505 (Orange) in the file? (Not really the same, but in principle the same effect as overprint 100% Yellow over the PMS-coloured elements regarding the "50% paperwhite" areas in the 50% spotcolour objects?)

I´guess "bigger" grafic elements / objects than "paperwhite" dots are meant, or not?

But you said also before, that the plates are fine, so there is a screen close to 50% on the exposured plate, that you can exclude a wrong overfilling of the bitmapped screen as a reason...

Ulrich

 

[Alith7]

Ulrich~
I think so? I'm sorry, your english is slightly hard to follow.
if you look a few posts back, I have a screen shot of the plate TIF's from the problem area. it is a bubble graphic, so it's not a perfect negative dot fill, and not a 100% flood yellow, but there is some overlap between the yellow and the PMS.

Also, maybe try explaining in German and I'll try to run a translate on what you write. It might come through clearer then. I know a very small amount of German from back in High School.

 

[Ulrich]

...I'm sorry, your english is slightly hard to follow.

How embarrassing... :-(

sorry, let me ask again so simple as i can:

You wrote: "There are no dots", but i see yellow dots in your first picture and orange in the second picture...

You wrote: Customer wanted to fill in the "white" areas of the screened PMS with yellow.

I understand: In your file and on the plate there are items (grafic elements), they are coloured with 50% tone of spotcolour orange (PMS 1505).

A nearby perfect print will reach about 63% (up to 4% more or less) on the coated paper caused by the increase printed with an 175lpi screen (a 200 lpi screen can cause a higher increase than a 175lpi, if not perfectly calibrated, i´m sure you know that...).

The other 50% in the file and on the plate (and ideal 37% "paperwhite" in the 175lpi print) should be filled up with yellow?
(Not with overprinting the same element in 100% Yellow, but the negative, white 37% "dots"?)

I could not believe that and that´s the reason for asking.

But if that should in fact be the aim, i think you have to consider, that in file and on plate 50% screen yellow already as bitmapped 50% screened dots causes also an increase of about 13% up to 20%. That causes naturally overlapping and it only works via bitmaps in the file, otherwise there are big problems with the angles for PMS and Yellow...

Next possible horror-feature in this context could be trapping the bitmaps in a wrong direction (not the right way increasing yellow to overlap orange (PMS 1505), but the other direction: Orange (PMS 1505) increased to lay under or over yellow...)

I want to apologize my inquiry, i really do not suspect your knowledge and you harvested already very good inspiration from others here and i guess they are nearer by the truth as my thoughts:

One looks at first to the ink and the other to the press, i myself (as a prepress-worker) looking for possible faults on my side first and my intention is just to make you really sure, that your view to the topics is correct ;-)



Should i really write you a german version? I would like to do that, but i also hope that is not neccessary ;-)

Sollen wirklich die "negativen" papierweissen Raster-Punkte in der jeweiligen 50% gerasterten orangen Pantonefarbfläche in Gelb gedruckt werden und das Gelb soll nicht Pantone Orange überdrucken?


Best wishes

Ulrich

 

[Alith7]

(snip)
Should i really write you a german version? I would like to do that, but i also hope that is not neccessary ;-)

Sollen wirklich die "negativen" papierweissen Raster-Punkte in der jeweiligen 50% gerasterten orangen Pantonefarbfläche in Gelb gedruckt werden und das Gelb soll nicht Pantone Orange überdrucken?

Best wishes

Ulrich

ok, I could translate it fine, I was even able to pick out a few words on my own without the translation software.

The file and screen angles seem to be correct. The question was what could be causing the screen to fill in completely. On the first attempt, the 50% screen filled in to 100%. There was no noticeable dot at all, just a slight waffle pattern.

On one of the later attempts, we did get it to work. Sort of, not really. the customer was happy with it anyways. However, the dot was still completely gone. (see first screen shot I posted) That is NOT a lighter PMS, that is the PMS 1505 at about a 30% dot that has blurred out to look like that.

On further discussion with my pressmen, we have decided that it is more than likely either an ink issue, or a lay-down order (we needed to put the PMS 1505 down first instead of last).

Thank you for your help!
Vielen Dank!

 

[gordo]

You might find this interesting.

PMS ink ordered from ink vendor screened at 40%

PMS ink ordered from same ink vendor screened at 40% but specified that is will be halftone screened

 

[keith1]

I would try the plate on one of the other units. I think that's been suggested a couple times already.
Could be the ink is too loose (runny).
Otherwise, to me, it's got to be pressure settings. Either roller pressure, or cylinder pressure (or both).
25 years experience could also be seen as 1 year, 25 times over

Keith

 

[Alith7]

(snip)
25 years experience could also be seen as 1 year, 25 times over

Keith

Laughing so hard right now!!!

 

[Alith7]

You might find this interesting.

PMS ink ordered from ink vendor screened at 40%

PMS ink ordered from same ink vendor screened at 40% but specified that is will be halftone screened

Gordo that's PERFECT!!
that will illustrate the problem WONDERFULLY!
thank you so much!!

 

[keith1]

A long long time ago, back in my press operating days, I had a problem with ink laying down properly. Many coworkers, & higher ups, shared their wisdom, to no avail. The better part of a day was spent.
I then discovered the problem. I had turned off a couple of the ink forms the night before and forgot to put them in contact again. It was one of those moments that when you grasp what you've done you get this sick swirl in the pit of your stomach and pray no one finds out.
It was years ago and I forget precisely how I covered for myself, but I let it be known that I had solved the problem. I expect I made it out to be far more technical than turning a couple levers. I sure as hell didn't tell anyone how dumb I was. I got away with it.
That's my segue into saying, I still think it's a pressure problem somewhere on that unit. It doesn't make a lot of sense that the ink you've been running all this time should suddenly create problems - barring that no one has been messing with the ink.
Actually I would have first suspected the plate. Bad batch, incorrect exposure, whatever. However you seem to have ruled that out. A 50% screen is not difficult. Even an AB Dick can handle that.

Keith

 

[curiosity]

Gordo that's PERFECT!!
that will illustrate the problem WONDERFULLY!
thank you so much!!

Not to be snarky (well maybe I am), but didn't Gordo suggest this solution in the very first response?

Don't get me wrong....the discussions that followed were riveting and all...but...just sayin'.

 

[arossetti]

Not to be snarky (well maybe I am), but didn't Gordo suggest this solution in the very first response?

Don't get me wrong....the discussions that followed were riveting and all...but...just sayin'.

I think at least three times Gordo mentioned looking at the ink and right after a new person to the thread then suggests checking the pressure.

 

[dabob]

I have been following this thread and glad that you got through it successfully but what about the ink tac? could it be that you might be running it in the wrong order????

 

[Alith7]

Not to be snarky (well maybe I am), but didn't Gordo suggest this solution in the very first response?

Don't get me wrong....the discussions that followed were riveting and all...but...just sayin'.

I think at least three times Gordo mentioned looking at the ink and right after a new person to the thread then suggests checking the pressure.

and I believe at least three times I agreed that that was very likely, and that we were going to talk to the ink vendor. Most of my responses after have been in response to other people who were trying to help with other possible ideas.

I also believe that Gordo was trying to show me why I needed a USB microscope, as well as helping to provide a visual of "why" ink might be the issue. being told "you need a different ink" only goes so far. Having a visual to show someone (especially pressmen and an owner who don't want to believe you in the first place) can take you the rest of the way. At no point did I hint, imply or allude that Gordo (or any of the others that suggested it might be an ink issue) might be wrong. My response was simply an enthusiastic thank you for his help in persuading people on my end. So why were either of these comments necessary?

 

[Alith7]

Keith~
ugh!! been there!! I know exactly what you mean about that sick twisting wrench in your stomach.
And I agree with you on being able to hold a 50% screen. that's why I started this whole thread in the first place.

 

[Alith7]

I have been following this thread and glad that you got through it successfully but what about the ink tac? could it be that you might be running it in the wrong order????

That was also a possibility that we are considering. We are going to try to put some test plates back on later this week to see what we can find out.

 

[dabob]

That was also a possibility that we are considering. We are going to try to put some test plates back on later this week to see what we can find out.

Just talked to our lead pressman about tac and laydown order, he said that this is the reason that you can't wet trap to a metalic ink . . nothing will stick to it and it will just squirm around and give you weird images . . .

 

[arossetti]

My response was simply an enthusiastic thank you for his help in persuading people on my end. So why were either of these comments necessary?

My commentary was an observation on the fact that a lot of people walked into this thread, read your original question, and proceeded to give their answer without reviewing the many comments already provided. Nothing to do with your agreeing or disagreeing with what Gordo offered.

 

[Slammer]

A long long time ago, back in my press operating days, I had a problem with ink laying down properly. Many coworkers, & higher ups, shared their wisdom, to no avail. The better part of a day was spent.
I then discovered the problem. I had turned off a couple of the ink forms the night before and forgot to put them in contact again. It was one of those moments that when you grasp what you've done you get this sick swirl in the pit of your stomach and pray no one finds out.
It was years ago and I forget precisely how I covered for myself, but I let it be known that I had solved the problem. I expect I made it out to be far more technical than turning a couple levers. I sure as hell didn't tell anyone how dumb I was. I got away with it.
That's my segue into saying, I still think it's a pressure problem somewhere on that unit. It doesn't make a lot of sense that the ink you've been running all this time should suddenly create problems - barring that no one has been messing with the ink.
Actually I would have first suspected the plate. Bad batch, incorrect exposure, whatever. However you seem to have ruled that out. A 50% screen is not difficult. Even an AB Dick can handle that.

Keith

Ha Ha, if you can´t blind them with science, baffle them with bullshit.

 

[Ulrich]

Ha Ha, if you can´t blind them with science, baffle them with bullshit.

LOL: very nice!!!

Ulrich